Working implementation of Contextual Undo pattern

Also, fix ArrayAdapter implementation with a defensive copy
Also, use Collections.addAll wherever possible

Still some duplication in the onTouchListener used in the swipe to dismiss
All code is uncommented, except for the important warnings
Remove useless comments
Fixed license
Added licensing
Removed abundant methods
Added modifiers
Removed abundant methods
Renamed variables
Moved and renamed some fuctions
Moved contextual undo example activity
Recreated ContextualUndoActivity
Use position for callback instead of item
Prettified undo state
Merge branch 'frankiesardo-master' into dev
Shortened performDismiss animation time
Before canceling current animation, check if new animation would be for current animation. If so, don't cancel. Should fix #5
Added reset function to AnimationAdapter.
Bump version to 1.9
Updated files to 1.9