iOS 7.1 changed the behavior for setting the title on disabled buttons.
Merge pull request #54 from square/puls/fix-ios-71

iOS 7.1 changed the behavior for setting the title on disabled buttons.
Fix not-this-month buttons on iOS 7.
Merge pull request #56 from square/puls/fix-not-this-month

Fix not-this-month buttons on iOS 7.
Merge remote-tracking branch 'parent/master'

* parent/master:
  Fix not-this-month buttons on iOS 7.
  iOS 7.1 changed the behavior for setting the title on disabled buttons.