Added new HMSegmentedControlSelectionStyle of Arrow

Also fixed some title positioning math:
-the title label position is now vertically adjusted for when the
HMSegmentedControlSelectionIndicatorLocation is Up or Down
-Title is now properly centered within it’s segment.
Merge branch 'master' of https://github.com/mrtristan/HMSegmentedControl into mrtristan-master

Adds HMSegmentedControlSelectionStyleArrow and fixes some title positioning math.
Minor code style refactoring