Since the second-player code was the first code I wrote, it was implemented
poorly. At that point, I didn't know the code base at all and the way it was
written would prevent anyone from ever adding to those parts.
The rewrite allows me to use the default geo.inc.c file for Mario, and removes
all of the geo2.inc.c files. I no longer do a bunch of bit shifting to figure
out which player is being drawn in the rendering code.
I'm also now able to remove tons of duplicate code that exists just for the
remote player. The main player code is generic enough to support both indices.
A side-effect of the rewrite is I was able to remove many assumptions in the
code where two-players is assumed, but many other parts of the code still
assume two players.
This is a fairly major change that, if all goes well, will be completely
unnoticed by the player. However, I do expect new bugs to pop up in strange
places. Time will tell.
