Output release gamex86.dll into baseq2 directory.
Allocate buffers for images on heap instead of stack.
Add software texture upscaling.

Maximum texture size is now set to 1024x1024. OpenGL 3.2 (and perhaps earlier, I haven't dug back further) requires this at a minimum-- I don't think it's worth supporting a video chipset that cannot meet this requirement.

The gl_texscale controls the scaling factor. If upscaling, we use the xBRZ algorithm to upscale the image before we upload to the video card.

For upscaling, gl_texscale can be set to values between 1.0 and 5.0. xBRZ only operates at integer multiple levels, so while fractional multiples will be honored, there'll be an extra software scaling step.

gl_texscale can also be set to values between 0.0 and 1.0 for downscaling, effectively replacing gl_picmip.