Support mmjs v2 API; don't lowercase Leaflet URLs
Support mmjs v2 API; don't lowercase Leaflet URLs

We now test for the existence of MM.Template and use it if it exists, rather
than (silly me!) assuming the existence of MM.TemplatedMapProvider.

Also, Leaflet URL templates aren't just lowercased entirely; we just lowercase
the template bits now.

stamen/maps.stamen.com,stamen/maps.stamen.com,mattb/maps.stamen.com,stamen/maps.stamen.com,mattb/maps.stamen.com,mattb/maps.stamen.com