new googleMap plugin for ZenPhoto

Uses :
- CodeIgniter Google Maps API V3 Class (hacked for zenphoto needs)
(https://github.com/BIOSTALL/CodeIgniter-Google-Maps-V3-API-Library)
- markerClustererPlus library 2.0.15
(http://google-maps-utility-library-v3.googlecode.com/svn/tags/markerclustererplus/)
- overlappingMarkerSpiderfier library 0.3
(https://github.com/jawj/OverlappingMarkerSpiderfier)