Fixed an issue when QX86_E_INTERNAL would be returned instead of QX86_E_INSN_UNDEFINED
This issue manifested only on opcode maps smaller than the full 256 size, such as ModRM maps.
A number of bug fixes

This commit fixes several bugs in 64-bit mode decoding.  This manifested in PUSH
instructions (50 + r) and MOV instructions (B8 + r), and also when 32-bit
immediates were extended to 64-bit.

A rare-occurring internal problem has also been fixed.

Finally, for Python 3 compatibility, the map2c script was patched.