remove unused variable
fix punctuation in error messages :neckbeard:
throw an error if Google Maps API is not present
Allow route origins to be a string or array

maps will automatically geocode an origin or destination that is a 
string. Now routes can be drawn with lat lng array or an input string.
wrap it!
Merge pull request #177 from frodsan/bomb

:bomb:
Merge pull request #178 from frodsan/google_maps_required

throw an error if Google Maps API is not present
Merge pull request #179 from tmanderson/patch-1

Allow route origins to be a string or array
Update README
Improve event binding at adding markers, polylines or polygons
Support for removing Fusion Tables and GeoRSS/KML layers with removeLayer