Add MMDrawerController

Insert MMDrawerController for left side drawer menu in
PageViewController. Set up gestures for opening and closing drawer
menu. Drawer menu controls are not yet hooked up.
Fix black bar in fullscreen on iOS 6 with MMDrawerController

MMDrawerController container wasn't properly resizing on iOS 6
when transitioning to fullscreen, leaving a black bar at the top
of the screen. Manually set the frame of the MMDrawerController
when entering and exiting fullscreen mode to fix this.
Synchronize userprefs when fullscreen set
Hook up index in left drawer

Selecting 'Index' in the left drawer now pushes the center nav
controller to the index view. Navigating through the index still
pushes from category list to categories and from categories to
index pages, but once an index page is pushed onto the nav stack
the index back button will disappear, and the index can only be
accessed from the drawer again.
Fix offset when returning from fullscreen iOS6

Fix offset when returning from fullscreen in iOS6 or lower. Check
OS version before applying offset. Handle landscape and portrait
cases.