mipmap levels were coming out hosed.
Adding a call to xglPixelStorei(GL_UNPACK_ALIGNMENT, 4); restores it to the
default setting which was getting set to something else in other parts of
the code.
GUI improvements contributed by Norman Vine.
3dfx.sh wrapper script now sets voodoo2 variables as well.
Start of support for user defined texture scale.
Start of support for precalculated texture coordinates.
