* Improve layout of error and maintenance scrrens

* improve header on update pages

* use svg logo as default

* update screenshots

* updated flag icons

* remove lines completly

* Visitors in Real-time

* added ti flag

* fix merge

* readd logoHeight

* remove flags from plugins/UserCountry/images/

* change flag directory

* (hopefully) fix all tests

* UserCountry system tests

* Fix tests refs https://github.com/piwik/piwik/pull/11553

* Fixed CustomDimensions tests

* remove unused flags

* remove flag of united nations

* System tests with new path

* light border around flags in goals and live view

* Fix BC system test

* border around flag in visitor profile

* Border around country flags in reports

* border around flag icons in HTML reports

* simpler css

* System tests

* UI tests show new flags + borders around them

* replace archives if they already exists instead of ignoring them

* adds a simple test to prove archives are replaced now

* improve test

* use report property to enable/disable flattener

* update tests

* Update changelog [ci skip]

* minor renamings

* Issue #11450

Add clarification in emails about new version for super users

* Revert "Issue #11450"

This reverts commit ed5d25a20677f7e33a2eaff1e621334cbee65c19.

* #11450 correstions based on feedback

* #11450 test fix

* add icons submodule

* replace path

* change submodule url

* fix JSONTest

* fix integration tests

* update icon submodules

* fix preg_match

* fix remaining system tests

* better match for non dist icon files

* fix .gitmodules

* update icon submodule

* Fixed custom dimension test

* Do not completely fail when GD not enabled

* Fix http test + refactor checklist

* Refactored the code into a method

* Changed icon path refs https://github.com/piwik/piwik/pull/11383

* System tests

* Update valid UI tests

* Fix integration test

* System tests: enable images generation in scheduled reports

* prevent error if report does not support multiple periods

* updates expected test files

I know the temporary table only exists during session, but problem is a possible error `PDOException: SQLSTATE[42S01]: Base table or view already exists: 1050 Table 'tmp_log_actions_to_keep' already exists` when logs are purged twice during a session. 

We could use `if not exists` when creating the table but then we would still have the entries from a previous "delete logs run" in there.

I noticed this error in tests but it may also occur in a regular task schedule that purge logs is called twice if eg implemented by a plugin and by privacy manager etc.

Interesting! I think this solves #11536. (ref. http://stackoverflow.com/questions/18645493/css-animation-difference-between-left100-and-translate100 )

* Upgrade to Raphael 2.2.7 to fix serious memory leak in UserCountryMap

Kartograph stores data on SVG paths using Raphael:

https://github.com/kartograph/kartograph.js/blob/f70bd295fa8b763d771f923a91b09564040eada3/src/core/maplayerpath.coffee#L30

Raphael stores this data in a *global* map, keyed on the path's ID:

https://github.com/DmitryBaranovskiy/raphael/blob/fe8e591e1c86b5aeb4c252b33c08e647434504c5/raphael.js#L3168

https://github.com/DmitryBaranovskiy/raphael/blob/fe8e591e1c86b5aeb4c252b33c08e647434504c5/raphael.js#L306

UserCountryMap does the right thing and calls clear() on the Kartograph map to reclaim memory...:

https://github.com/piwik/piwik/blob/6fab62e2229f9efadbcf43ff541b46f007fc6323/plugins/UserCountryMap/javascripts/visitor-map.js#L1332

...which eventually calls `remove` on each of these SVG paths:

https://github.com/kartograph/kartograph.js/blob/f70bd295fa8b763d771f923a91b09564040eada3/src/core/maplayerpath.coffee#L70

However, previous versions of Raphael (including 2.1.0) fail to call `removeData` to clear out the data associated with the SVG path in the global map,
leading to a serious memory leak (heap grows by ~10MB each time the map refreshes):

https://github.com/DmitryBaranovskiy/raphael/blob/7ba1a8258be64fdb517bc78fde44ff0e6188ca05/raphael.js#L4475

Later versions, including the latest 2.2.1, properly call `removeData` when `remove` is called:

https://github.com/DmitryBaranovskiy/raphael/blob/master/raphael.js#L6842

* Properly remove window resize event listener for UserCountryMap

The previous version of the code inappropriately tried to remove the event listener;
the `function` object for `onResizeLazy` is different across maps.

* Prevent visitor-map from inserting a new CSS document into DOM every refresh.

* Fixes memory leaks in dataTable and jqplot via uncleared resize handlers

Previously, these plugins registered a handler on the `resize` event on window,
but used ad-hoc heuristics to determine when to remove the handler:

* dataTable would only remove the handler the next time the `resize` event fires,
  which is not guaranteed to happen regularly (especially if the user is not
  regularly resizing their browser window, e.g., it is full screened)
  * Fix: I define `_destroy` on `dataTable`, which appropriately cleans up the
    handler (and calls the `_destroy` method of its parent class, `UIControl`)
* jqplot contained code to remove the `resize` listener when `destroyPlot()`
  is called, but a) this function is not called when the plot is removed from
  the DOM (the code called `destroy()` on the `plot` object directly), and
  b) it incorrectly uses `this` instead of `self`, preventing it from working
  in the first place.
  * Fix: I fixed the `this`/`self` confusion, and changed the cleanup code
    such that `$.jqplot.visiblePlots` contains `JqplotGraphDataTable` objects
    rather than `jqplot` objects.

These event handlers prevented previous jqplot and datatable objects from being
garbage collected each time the dashboard is refreshed.

* Prevent leaking data tables via body mouseup handlers.

Adds code to clean up mouseup handlers on the body HTML element when data tables are destroyed.

Previously, these handlers caused data tables to remain in memory forever.

* Update overlay.css

Fix for #11510 – needs testing.

* Update overlay.css

hide overflow for y as well as x

Updates method documentation of `broadcast.buildReportingUrl`

Previously, every `UIControl` ever created would be stored in `UIControl._controls`. During cleanup, every `UIControl` would be checked to see if it is still active in the DOM, but would never be removed from the array.

Now, cleanup only retains a reference to active `UIControl` instances. This change also decouples `UIControl` IDs from the length of the array.

* Improves plugin list filters

* match lowercase

* update ui tests

* fix #11512 Premium Plugin Installer shows false error message after install

* better handling when a plugin was installed

Fix showColumns in Multisites API by pageviews does not work

* Update followingpages.js

Fix for #11509

* Update followingpages.js

better css, allow for smooth transition and more control.

* Update client.css

add transition css.

* Fix Overlay bubbles on Firefox (and Opera Mini)

The previous css didn't work on firefox (http://caniuse.com/#search=zoom). Using transform: scale() is the recommended way to do it according to

* Update client.css

* show human readable value for default values

* update screenshots