import-from-gallery: more sanity checks.
Target Android 2.3.7+
Updated sources from Gingerbread's Gallery.apk
Merge branch 'develop' into feature/gingerbread-gallery

Conflicts:
	res/layout/cropimage.xml
Updated README.md including reference to CropImageIntentBuilder.

Also removed Android 4 notes.
Merge branch 'feature/gingerbread-gallery' into develop
README: removed
README: updated to include information about CropImageIntentBuilder
Added contributor's policy