offline access to map tiles

[robynitp]

collecting some info on this issue:

• https://www.npmjs.com/package/offline-leaflet-map
• http://davidrs.com/wp/phonegap-3-0-leaflet-offline-maps/

[robynitp]

http://stackoverflow.com/questions/16036880/how-to-make-offline-mapsusing-leaflet-osm-by-caching