Build 2820
SVN-
factor out y panning coefficient calculation code.
SVN handles and Git names are merged into one person.
factor out y panning coefficient calculation code.
don't attempt to draw sprite with void tile, preventing div-by-0s later
fix mirror-related oob access analogous to r1872's fix for classic.
When drawing from inside the mirror, there may be no 'bunches' (BUILD lingo, not TROR ones) collected, but following code used the first one unconditionally.
with r_parallaxskypanning=1, clamp the sky at a constant horizon.
See E4L1 for what this means.