[develop] Performance Improvements (Markers, MarkerClusterer Rewrite)

Performance tweaks

- lazyUpdate map.coffee
- modelsByRef to disable equality checks
- marker managers improvements (MarkerClustererPlus dropped from google tools sdk)

This is to open up this major PR for discussion how to handle merging in these changes.
Removal of this may be a conflict especially in the cases for dealing with marker "flash". However if this is handled in the new MarkerManager's then this is a mute point. One thing to consider though if this flow gets killed then Managers should be written for shapes, polylines.. etc.