Fix issue 351: Vertical text alignment

NIAttributedLabel.verticalTextAlignment stopped working correctly in
commit c856b9b.
kCFCoreFoundationVersionNumber_iOS_7_0
Merge pull request #374 from mmorearty/patch-vertical-text-alignment

Fix issue 351: Vertical text alignment
Merge commit 'fd4d255dc056ce35e9d429cb926c69a6345aad93'