Rechargeable Tools

This adds a few things:

New flags:
'INTERNAL' vpart flag - Requires part to be installed on the same tile as a vpart with the 'CARGO' flag.

'RECHARGE' vpart flag - Recharge items placed inside that have the same flag.
'RECHARGE' item flag - Get recharged if on the same tile as a vpart with the same flag.

New item:
recharge station - This is the new vpart that allows the vehicle battery to recharge tools with the 'RECHARGE' flag.
rechargeable battery mod - Turns tool it is applied to into one able to be recharged with the recharge station. The tool WILL still 'U'nload, but the player receives no batteries.