HACK: A much more radical tweaking of var, that sets it to zero upon construction of ANY object. This will certainly need to be tied to a compat flag; in addition, I didn't read all of write_object_data, so some "prefixes" or related might cause problems later.
Temp: make all variables initialize to zero.
Bugfix: textureStructs was mutilating its own indices over time; replaced with a map and a "re-use" set.
Merge branch 'texturecache_fix' into gm5_compat
Provisional fix for texture overwrite issue on other graphics backends.
Merge branch 'texturecache_fix' into gm5_compat