Pan Tilt mount for ProtoTank

This base is designed to used with timmiclark's ProtoTank (http://www.thingiverse.com/thing:972768), and was adapted from the Pan/Tilt camera mount at http://www.thingiverse.com/thing:708819 by fbuenonet. In addition to the design by fbuenonet, there are a number of other Pan/Tilt camera mounts out there on Thingiverse, for example, http://www.thingiverse.com/thing:350229 and http://www.thingiverse.com/thing:1242570.