Drawer offset for positioning drawerView
Added shadowViewEnabled to toggle shadowView
Added showAnimationDuration/hideAnimationDuration for setting custom animation duration for showing and hiding drawer
Shadow view enabled by default.
Fixed an issue related to multiple panning cells but removing superview for drawerView and shadowView is problematic. Fixed gestureRecognizerShouldBegin to recognize self and drawerView. ADded delegate method for panningTableViewCell:shouldRecognizeGestureRecognizer:simultaneouslyWithGestureRecognizer:. Added delegate method for panningTableViewCell:shouldPanWithGestureRecognizer:. Added support method for checking if panning is in progress. Added setDrawerRevealed with completion block. Added gesture recognizer getters.
Merge pull request #30 from mpurland/master

Fixes and updates for drawer offset, properties, duration, and multiple panning.