Added splash screen again.
Rename and separate methods in WebAppAllocator which were beginning to confuse things.

This clarifies a lot. So refactored the install flow such that:
 * WebAppDispatcher actually does the allocation of the slot for the web app.
 * GeckoApp mutates WebAppAllocator.
 * WebAppImpl reads from WebAppAllocator.

Furthermore, we are able to now start making InstallHelper useful for post APK install, pre-first run.
Move all webapp installation initialization into this class now.
When opening web apps, make sure we go through the APK’s launcher.
Removed unused strings.
Moved Context argument to constructor of ApkResources. Saves a lot of exception catching.
Move calculation of icon color into InstallHelper.

WebAppAllocator doesn’t need to know about Bitmaps, just color.
Use the install helper to do web app install immediately after APK install.