Adding a pin icon for the pins, instead of a red square

Hopefully correctly attributing http://sweetclipart.com/ for their blue pushpin
Correctly place the pin upon creation
Refactoring
Minor changes, adding NSStringFromMRMapCoordinate
Starting to add drag support to pins
Adding updatePinMethod block signature and property
Adding pin coordinate update callbacks
Implementing MRBuiltinPin's drag:
Adding an animation for pin lifting
Splitting out newPinForIdentifier:
Making addPin: support dragging new pins
Forgot UIScreen.scale is >= 1
Restricting drags to the rect defined by pinHandle, breaking out pin ivars