18650 Battery Storage slide top box - dual battery

Remix of the 4 battery box which I quite liked, but wanted in a 2 battery form factor. Makes the top a bit tighter but can be opened with a fingernail. Link to the original 4 battery box - http://www.thingiverse.com/thing:810373 Updated March 17 - added separate files for box and lid in case of difficulty printing together.