Immerse: a combined movement and camera immersive effects mutator for GZDoom

Leaning and RealAim code by Joshua Hard.

Immerse uses (a lot of) code from:
	Tilt++ by Nash Muhandes
	Footsteps by Benjamin Moir
	
It's as much their work as my own; I just stitched it all together and made them
all play nicely with one another.

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Footsteps Credits:

Ral22
    Supplying the vast majority of default sounds