Add support for blurred background view

Added support for blurred background view on iOS7 and tinted background
for iOS6.

Added support for iOS7 status bar styles by taking into account whether
a background view is displayed or the brightness of the background
color.

Fixed a lot of bugs with iOS6.
Fix small oops in iOS6
fixed issue #26 with screen being too low
Merge pull request #27 from CaptainMalReynolds/master

fixed issue #26 with screen being too low
Merge branch 'master' into develop

Conflicts:
	ABPadLockScreen/ABPadLockScreenView.m
Merge branch 'master' of https://github.com/abury/ABPadLockScreen