[2/3] OmniGears: omniswitch as default recents

OmniSwitch provides broadcast events for showing
and hiding the overlay

We need to make sure that OmniSwitch service is really
running else we will get no recents at all. Also on startup
it will take some time until the OmnISwitch service
has been started.

OmniSwitch will send a service start and stop broadcast
that will guard the usage of OmnSwitch

PS3
added first time alert to make sure users get noticed
to enable OmniSwitch when they enable usage for recents
added category and rework strings

PS4
I hate whitespaces

Change-Id: I96a103d09ece80f782387fd2e24104545461b6a5
Merge "[2/3] OmniGears: omniswitch as default recents" into android-4.4