Set alpha depending on progress at completion time

Otherwise, there's a race condition where alpha will be set to 0, 1,
and then 0 again if setProgress:animated: is called in quick enough
succession (basically, within the animation duration).
Merge pull request #26 from stephencelis/master

Set alpha depending on progress at completion time
Refactored intercepting implementation
Fix #27: Use NSNotificationCenter instead of UINavigationControllerDelegate
Removed inner dependency to MRMessageInterceptor
Merge pull request #28 from mrackwitz/fix_NavigationBarProgress

Fix navigation bar progress
Extended Example app to test if you can go deeper and the progress bar is faded out
Update README.md
Merge pull request #29 from mikker/patch-1

Add missing ` in README.md
Fixed #30 for new behavior since iOS 7.1
Bumped version to 0.4.2
Fixed #31 for new iOS 7.1 behavior
Merge pull request #32 from eni9889/bugfix-activityindicatorview-ios7

Fixed #31 for new iOS 7.1 behavior
Call tintColorDidChange on initialization for all UIView subclasses
Bumped version to 0.4.3
Update README.md

New flat badges from shields.io
Changed MRActivityIndicatorView notifications to take an argument of NSNotification rather than NSNotificationCenter
Merge pull request #33 from owenworley/master

Fix MRActivityIndicatorView notification methods
Exposed line width and border width on MRCircularProgressView