AnimatedCluster strategy for OpenLayers

Cluster strategy for OpenLayers that animates clusters on zoom change.

A living demo can be found at in the demo site. More information on this strategy can be found at the acuriosanimal blog:

• AnimatedCluster pan related bug… fixed !!!
• Improved performance on the AnimatedCluster for OpenLayers
• AnimatedCluster demo site updated to work with OpenLayers 2.12
• Animated marker cluster strategy for OpenLayers