Switch Lua 5.3 off bit32 dependency

[nvs]

This would have it be required only for Lua 5.1, which is fine. The same functionality can be fulfilled using bitwise operators introduced in Lua 5.3. So the LUA_COMPAT_BITLIB compilation option would not matter. This would also provide better forwards compatibility with Lua 5.4.

Some quick testing shows that this won't really change performance in Lua 5.3. Perhaps ~1.5% slower for a fully compatible version of band. And roughly parity for a version that is simply A & B, and nothing else. I will think about this more once Lua 5.4 is released.

[nvs]

A bit of reading shows that Lua 5.3 without the compatibility library will still provide a bit32 library that returns false. In short, one would need to use the native bitwise operators for Lua 5.3+.

[nvs]

Testing shows that so long as the bit32 library is installed (e.g. via Luarocks), all will be well for Lua 5.3 compiled without LUA_COMPAT_BITLIB . Thus this is closed.