1) GLdouble was incorrectly being treated as GLfloat which is now broken
with -m4-single as default. Fixed.
2) Implemented all missing double-precision vertex attribute reader
functions.
3) Implemented all missing vertex reader/extracter functions for
unsigned/signed ints and unsigned/signed shorts.
4) Added (void) argument lists to every function missing them.
- Not the same as accepting no arguments in C, as with C++.
5) Added KOS's __restrict to software.h so it can be used in common code.
