OOIION-1629
Increase cluster grid size so that more neighboring pins are slurped into a cluster (+) pin.  Now the cluster size matches the actual size of the cluster pin . . . i.e. if a normal pin 'touches' another it gets slurped into a cluster pin.
Merge pull request #251 from cgalvarino/resize_cluster_grid_size

OOIION-1629