* Add generate:angular-component command to generate an angular component.

* Do not modify Date prototype.

* Move period selector code from calendar.js to new angular directive (just move, no refactoring).

* Extract date picker code from period selector code and put into new directive.

* Extract range picking code into separate component than period selector.

* Extract single period calendar to separate component & extract period specific functionality to new extendable periods service.

* Fixing regressions in period selector behavior.

* Move bulk of period selector code from directive to controller, & fix variable name in date range picker template.

* Fix issue w/ yesterday date value, remove need to give period selector directive translations and make sure periods can be extended in the frontend.

* Make sure period selector still works outside of an angular routing context (ie, in embedded dashboard).

* In period selector UI test, hide ajaxLoadingCalendar using CSS since it is now managed by angular.

* Make sure selected period highlighting changes immediately after selecting, even if loading a new page.

* Put period selector top level element ID & classes on correct elements to ensure certain styles work properly.

* Make sure selected period text changes immediately after selecing period, even if loading a new page or changing the URL.

* Make sure range start/end changes immediately when a period is selected & selected period date range stops being highlighted immediately when a range period is selected, even if loading a new page.

* Updating expected screenshots.

* Updating screenshots.

* Assorted fixes for period selector refactor.

- Filter out invalid period labels (can happen if INI config for allowed periods is incorrect).
- When determining display text for range, don't try to format the startRangeDate/endRangeDate vars, they're both strings.
- Use correct selector when closing period selector.

* Set global piwik date/period values on location change, outside of period selector component.

* Do not skip parsing date if it does not start with an int (since the JS can handle today/yesterday/now).

* Assorted fixes for period selector refactor:

- use $onChanges instead of watches in datepicker (watches get triggered every time, $onChanges doesn't)
- don't use arrays for selected/highlighted dates (for some weird reason, changing one of these arrays results in angular thinking it changes 3 times instead of once)
- don't redraw on triggered mouseover events (something triggers mouseover when a date is selected, probably jquery datepicker)
- draw after a setTimeout when a date is selected so our drawing occurs after jquery datepicker draws

* Achieving smoother rendering for period selector by removing click handlers jquery datepicker adds.

Also fixed bug where selecting the current period type reset the view date for the date picker.

* Bound range date in period selector by piwik min/max date, so inferred dates will always be within allowed pickable dates in picker.

* Removing ES6 used by accident + fix for issue when switching from non-year to year period (ui-datepicker-current-day class does not get removed).

* Fix for angularjs one way binding quirk: initial property value is set before $onInit not during construction.

* Avoid an exception when a date input in the date range picker is empty.

* Split up change/keyup event to solve strange race condition in IE 10 on browserstack.

* Change period selector "click again" tooltip to "double click".

* Remove tabindexes > 1 so period selector control can be tabbed through.

* Show visual cue for invalid dates in date range picker.

* Only hide period option tooltip if period is active period, not if period is selected period.

* In period selector, disable apply button if range is invalid. Also fix case when \$.datepicker.parseDate returns null instead of throwing.