Adding the ability to push side panels rather than overlap them
Fix center animation

Added `UIViewAnimationOptionBeginFromCurrentState` when animating
the center panel. This fixes glitchy behavior when there is a
`UIToolbar` in the centerpanel with a overridden
`layoutSubviews`. Without this option the buttons in the
`UIToolbar` would be jumping around before animating into place. It
probably fixes other components with overridden `layoutSubviews` as
well.
Merge branch 'animationfix'