Commander's viewport rotation can be misaligned with tank cannon's rotation

[Andrew Theel]

Steps to reproduce:

• Select crewman
• Jump into various tanks
• Switch to turret
• Rotate at various degrees while firing
• Notice the misalignment on many but not all tanks

Known turrets: Firefly British Stuart PIVJ Sdkfz234(1) a few if not all others

[Andrew Theel]

We tested more and tested better, apparently it can happen on many more tanks that I first thought. It has to deal with firing while rotating or something. It would not happen at all on some vehicles, but it was a bit touchy to get to happen.

[Colin Basnett]

Happens consistently on the long-barrel Panzer III.

[Matt Hands]

Should be fixed in commit 3419a42.

Includes a new bCamOffsetRelToGunPitch option, for when any camera position offset (ViewLocation) needs to be relative to the cannon's pitch, e.g. for open sights in some AT guns.