Fixed Issue #152 & improved iOS 7 status bar view

By fixing #152 I discovred that there was also no longer the need for
`dummyStatusBarView`. MMDrawerContoller's view can simply be used to
display the `statusBarViewBackgroundColor`. It also has the benefit
that the drawer's shadow doesn't get cut off.
Quickfix of strange issue where left drawer gets blank

https://github.com/mutualmobile/MMDrawerController/issues/30

For some reason self.centerContainerView.frame.origin.x is sometimes being set to 0.5 at the end of close animation. This causes drawerFullyCovered to be incorrectly set to false. 

Note: This is just a quickfix. The actual reason of why origin.x is being set to 0.5 in the first place should be investigated and corrected in a future version.
Merge commit '62164d834458ce09b0f0a7ad5394186343a03a5d'
Merge commit '1c1f79a1f963e92704a05d4296b92b22410d4f0d'