Titles, fall through, and view rectangles

[andygeers]

There's three key commits here introducing three improvements:

1. You can now add an optional title to each coachmark, that will be displayed in a different font (default is bold)
2. You can optionally specify that if the user taps inside the highlight area, that tap should "fall through" and terminate the coachmarks so that the user can interact with what they have tapped on (in my app I enable this for the final coachmark of each set)
3. Instead of manually specifying a rect or POI, you can now specify an "attachedview" (and optional "transform") and the coachmarks will be positioned at runtime to match that view