Themes: Avoid compiling icon packs every boot

Change-Id: I51c7effdd4592a302f457822a05cbebee6cde06b

Conflicts:
	services/java/com/android/server/pm/PackageManagerService.java
Cleanup app->{theme1,theme2...} mapping on uninstall

Change-Id: I24b43e8817db1927d5b43fcf7ad3340269d046ea