Bug 920445 - [Flatfish][homescreen] fix search_page enabled customization

- remove unused dom elements
- update test
- update tablet customization settings
Bug 913397 - [Keyboard] Make keyboard app support 1.5x graphics
Bug 920561 - Ensure LazyLoader.load does not slow down app rendering. r=etienne,kaze
Merge pull request #12830 from vingtetun/lazyload.no.in.apps.startup

Bug 920561 - Ensure LazyLoader.load does not slow down app rendering. r=...
Merge pull request #12572 from EragonJ/bug-920445

Bug 920445 - [Flatfish][homescreen] fix search_page enabled customizatio...
Merge pull request #12285 from luke-chang/913397_keyboard_1.5x_graphics

Bug 913397 - [Keyboard] Make keyboard app support 1.5x graphics, r=rudylu