Added demo for opening side view at beginning.

See #333.
Fix distance calculation for panning animation when you are panning
right.
Refactored the init methods of IIViewDeckController, in particular,
the initWithCoder: and initWithNibName:bundle: methods.

These methods should chain invoke their super methods. Not doing
so causes some behaviors to break. For example, without chaining
to initWithCoder: in the super class, you can't setup segues in a
storyboard for use with the class, because the segues do not get
created.

The fix is simply to call the appropriate super initializer, and
then call a common method that initializes other properties.
Exposed center & side controllers as IBOutlets. Same for panningView.
Added Accessibility Label, Hint, and Frame to centerTapper. #227

This should resolve issue #227 - Unable to close left view while in voiceover mode.
Fixed behavior of the IIViewDeckNavigationBarOrOpenCenterPanning mode.

This should enable the desired behavior described in issue #348.
Merge branch 'develop' of github.com:Inferis/ViewDeck into develop