Themes: Install themes and icon packs for secondary users.

Change-Id: I48ae6835223510a433642fced5b96b6c3954baf6
Themes: Remove DEFAULT_THEME_APPLIED_ON_FIRST_BOOT

doApplyDefaultTheme should be able to apply the default theme, if
one exists, whenever applyDefaultTheme() is called.

Change-Id: Ia50b4089d122855a4ddde91a02eef33ed3f9eaf4

Conflicts:
	core/java/android/provider/Settings.java