Adds drop shadow view and improves alpha.
Adds drop shadow view and improves alpha.

OliverLetterer/SPLDrawerViewController,1yvT0s/SPLDrawerViewController,OliverLetterer/SPLDrawerViewController,1yvT0s/SPLDrawerViewController,1yvT0s/SPLDrawerViewController,OliverLetterer/SPLDrawerViewController