add broadcastReceiver to receive foreground information.
add change brightness method in app level.
prevent show manage app itself in list. Change app list logic to onResume so can get updated app list.
fix NULL Pointer typo.
add api getIcon for MyPackageInfo.
list all apps in luncher instead of dirty detect.
refactor MyPackageInfo class to support both PackageInfo and ResolveInfo.
Meaningless because normal sdk doesn't have intent to inform activity pause and resume.