Merge pull request #8 from nicoyuste/master

Improvements in the animation and the algorithm of spliting and joining
Rename delegate from MKMapViewDelegate to REMarkerClusterDelegate
Use cluster title
Original code formatting
Original code formatting
Remove unused code
Original code formatting
Original code formatting
Original code formatting
Original code formatting
Add note about contributors
Version bump (2.2)
Version bump (2.2)
Add another contributor
Add another contributor
Update readme