Vertical text cropping

If the label bounds are not high enough, CTFramesetterSuggestFrameSizeWithConstraints returns CGSizeZero and no text is rendered at all. By setting the text rect height to be twice the font point size, CTFramesetterSuggestFrameSizeWithConstraints doesn't return CGSizeZero thus the text is rendered cropped.
Adding more detail to inline comment about doubling point size
Merge branch '0xced-vertical-cropping'
Merge branch 'master' of github.com:mattt/TTTAttributedLabel