Add script for building with Crosswalk
Add showSpinner option to activity index page
Switch min Android API to 16 (i.e. 4.1 Jelly Bean)

This seems stable now that we're using Crosswalk.
Switch min Android API to 15 (i.e. 4.0.3 Ice Cream Sandwich MR1)
Add hack to force rescrolling of the screen on smaller screens
Ignore user-specific ant.properties file
Merge branch 'master' into african-lions

Conflicts:
	android-custom-files/AndroidManifest.xml