HUD and MPD/MFDs now updated

Fighting for screen space, the HUD and MPDs were getting out of hand. You can now set the scale of both elements by key presses or in the external .CFG file.

IHADSS (HUD) brightness controls also included. It just looked really good when you turned on the power.

I need to re-do all the OpenGL drawing for the MPDs as I move to use the same (-1.0 to 1.0) co-ordinate system that I used for the IHADSS. This makes scaling and multiple resolution support much easier to do.

The Linear filtering is not as clear as I would like when shrinking the MPDs down, to offset this you can increase the screen-resolution which helps a lot.

And for Christmas I would really like an extra shadow-stage for distant terrain shadow features. On a 10 meter per tile terrain, the existing 3 stages are too abrupt.