Merge pull request #1 from SINTEF-9012/master

Update to lastest version
Removing all markers
markers are optional in RemoveMarkers
Merge pull request #7 from FalloutPL/master

Allows removing all markers in PruneCluster.RemoveMarkers()
Readme fix
New example with custom icon
Merge branch 'master' of github.com:SINTEF-9012/PruneCluster
Remove PruneCluster.min.js.map
RemoveMarkers method documentation