Fix one shader in Alien that would not compile.

This is probably a shadow shader, missed StereoParams load line.  Matches other shader fixes, so taking it.
Move g_particle shaders out of Alien fix.

These are not fixed for one-eyed particles on Ultra with SLI.
Saved as possible future fix.
Move all crosshair shaders to .z param in Alien fix.

Not sure this is useful, but people might want to move crosshair independent of the HUD.  This allows that to happen, at the cost of moving some in-game effects to different depth, and messing with text in UI.

Default is still to set 0 as screen depth, as fewest problems.