Adjust final frame to avoid blurriness from half-pixels

Closes #39
Added calloutViewWillAppear and calloutViewWillDisappear Delegate methods
Merge pull request #40 from kimar/master

Added two new delegate methods (calloutViewWillAppear and calloutViewWillDisappear)
Ensure our accessory views are pixel-aligned
Better MKMapView example

- Demonstrate how to handle touches properly when presented in a MKMapView
- Demonstrate how to handle touches properly when presented in a layer
Merge pull request #1 from nfarina/master

Latest changes on official nfarina/calloutview repo