* updated browser and os icons (#11063)

* updated browser-icons

from https://github.com/Findus23/device-icons
72d5ffef94a597c4ba226b33344e0badaadc3c35

* added os icons

* added previous icons

* changed macOS icon

* replaced optipng with pngquant (36% size reduction)

* center icons vertically

* sharpen icons

* increased icon size to 48x48

* fixed visitorPopup and realtimemap

* revert css change

* fixed HTML-Reports

* replaced Windows icon

https://github.com/piwik/piwik/pull/11063#issuecomment-270221316

* max-width and max-height for datatables

* removed submodul (sorry wrong commit)

* add explicit max-size for dataTableRowActions

* fixed UNK.png

* first try at fixing system tests

* fixed cookie.gif

* updates icons in System tests

* updated plugin icons (#11121)

* updated plugin icons

* increased icon size to 48x48

* updated searchEngine and social icons (#11093)

* updated and added searchEngine and social icons

* removed unnecessary icons

* sharpen icons

* increased icon size to 48x48

* fixed promovideo socialicons

http://builds-artifacts.piwik.org/piwik/piwik/3.x-dev/21859/UIIntegrationTest_dashboard1.png

* fixed xx.png

* updates plugin icons in system tests

* [tests] RockMelt has it's own icon

* updates expected UI test files

* submodule update

* fix some last tests

* Two UI tests suite were  not running because of an authentication error in the UItestFixture

This should fix it

* Valid screenshot tests

* updated our font pack, use some material design icons

* fix sign in icon, better help icon

* fix ui tests

* fix more screenshot tests

* add legal notice and readme

* fix remaining  tests