Fix for the UINavigationBar and UIToolBar showing up as black on iPad.
Merge pull request #11 from jordanbrown/dev

Fix for the UINavigationBar and UIToolBar showing up as black on iPad.
Adjust density for screen size as well as image size.
Tweak density calc. Needs further testing on multiple device form factors.
Add provisional support for portrait upside down.
Expose blur radius and background dimming as options.
Rev to version 1.1.