Theme Manager v2.1 with backup/restore functionality.

PS2:
Let's ditch drawable-ldpi while we're at it.

PS3:
Drop usage of deprecated Gallery in favor of the PagerContainer
added to chaos support library.

PS4:
Add a cover flow style PageTransformer for viewing a theme's previews.

PS5:
Use VelocityViewPager from chaos support library.
Load all previews in an AsyncTask and show the indeterminate progress
indicator in the action bar while loading.

PS6:
Add license information to CoverFlowPageTransformer.

PS7:
Add page indicator to view pager when viewing a theme's previews.
Combine common elements of ThemeDetailActivity and ThemeElementDetailActivity
into a common DetailBaseActivity which both can extend.

PS8:
Set layout_height to 0dp and layout_weight to 1 in coverflow layout.

PS9:
Remove unused imports from ThemeDetailActivity and ThemeElementDetailActivity

Change-Id: I715e6b7806d6ac0f3fc87ecec0297dc0fa7e3102