Revision 2.0 Battery Holder

One problem with the PLA based holder clip was discovered after a very hot day of solar observing at the TXMOST museum. The fingers holding the battery "relaxed" after getting too warm, and no longer held the battery snugly. A new design was needed to strap the battery securely. This uses two separate clip pieces that go completely around the front of the pack and snap into slots in the base. They also have holes to allow viewing the voltage setting indicators under the straps.