Fix: markers should not not reappear after clear

After calling clusterkraf.clear() and zooming the map, all the previous
markers would reappear.
Merge pull request #18 from Jancorhw/clearfix

Fix: markers should not not reappear after clear
Update Android support library and Google Play Services
Merge pull request #19 from twotoasters/carlton-dev-supportlib

Update Android support library and Google Play Services
Merge branch 'master' of https://github.com/twotoasters/clusterkraf
Updated to add setShowClusterOnCentroid(boolean) which controls the
cluster location