Bug 1055299: Ignore continuous app launch request in homescreen side and send homescreen to background while rocketbar is open in system side

Conflicts:
	shared/elements/gaia_grid/js/grid_view.js
Merge pull request #24649 from alivedise/bugzilla/1055299_master/v6

Bug 1055299: Ignore continuous app launch request in homescreen side and...r=kgrandon