SlimRecents icon pack code cleanup and improvements [1/2]

now all glitches after switching from stock to slim and viceversa
should be fixed

stock and slim recents will use their own iconshandler instances
so this will be also good when porting slim recents to future android
version without the need to keep iconpack support for stock recents too

part 2 in frameworks base is for stock recents too

Change-Id: Icb5a26eded8e1a6083b19dd0fb993ff938f2a2bf