Map-enabled version of the Database activity latlong field.

Needs plugins local_map for map API, and datapreset_infomap_latlongmap for example of how to use the field with the database list view.

This is being built against Moodle 2.6+, but should work for at least 2.5.

If you're familiar with Git and can set up a test Moodle, the easiest way to try is to clone it from GitHub: https://github.com/Dave-B/moodle/tree/master-maps

This is a plugin version to help people unfamiliar with Git to try it; I'd like to get it included in core (MDL-42522).