Trebuchet: Fix double tab on home button

Ensure that all transitions are complete while processing new intents, creating a queue
of pending intents. This way every transition is executed properly.
JIRA: CYAN-1115
Issue: https://jira.cyanogenmod.org/browse/CYAN-1115

Change-Id: I74e5e2e14cc7515acd1eeef0cfddf7161992b11b
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>