Update google-maps-api.html with new API attribute

Updating the google-maps-api.html to include a new attribute that allows the developer to specify a Google Maps API for Business client id. Please see:
developers.google.com/maps/documentation/business/
https://developers.google.com/maps/documentation/business/clientside/
Merge pull request #8 from binaryaesthetics/patch-1

Update google-maps-api.html with new API attribute