Precious Metal update

I've switched the textures in Precious Metal over to DDS format, just as a test. The textures aren't big enough to give me any feedback on performance, however the size difference is interesting. I've heard there might be problems rendering these on a Mac, so I've kept the old textures around in case I need to revert.

The torque problem has been fixed using an idea from Ron Jensen in which a torque opposite to the engine torque (moments/l-prop-lbsft) is added to the FDM's roll section.