Add support for OpenStreetMap

[msimms]

Currently this uses Google Maps for map support, but this is not a long-term solution. Need to add OpenStreetMap support (can be optional) so I don't have to worry about going over the bandwidth limitations with Google. Note: An OSM mirror is also desired.

[msimms]

Basic OSM support is implemented. Still some cleanup to do - need support for infobox popups and as well as the ability to select a tile server.

[msimms]

This is working, just need to deploy my own tile server before using it in a production environment.