Bug 1037942 - Normalize alt in overwrite alternative layouts
Bug 1024333 - [v1.4][UX]Cannot turn off recent app page by tapping screen when "No recent app" is display

* Check if the cardsView is empty and should be closed or not in the onStartEvent event handler.
* Add test for closing empty cardsview by touchstart.
Merge pull request #21427 from begeeben/1024333_no_recent_app

Bug 1024333 - [v1.4][UX]Cannot turn off recent app page by tapping screen when "No recent app" is display, r=alive
Merge pull request #21654 from timdream/keyboard-alt-sublayout

Bug 1037942 - Normalize alt in overwrite alternative layouts, r=rudyl
Bug 994571 - [System2] Remove the pattern to return self in start()

* Remove 'var module = new Module().start()' pattern.
* Remove 'return this;' expression in start() function definitions.