Was intended as a simple code improvement, however it also seems to make WinMain, MxString::operator=, MxDSFile::Open 100% (all of which just needed registers to be switched around)
* Use bitfield for MxVideoParamFlags
Using a bitfield for MxVideoParamFlags results in the same xor/and logic that was partially inlined in the header file. This approach is a lot cleaner and there's a good chance this is what the devs would have landed on.
The code generation is really finicky -- other inlines in the header influence the code just by being there -- so I decided to stub out all of them. This got the match to 100%.
While I was in isle.cpp::SetupVideoFlags, I changed the signature so that the `m_using16bit` parameter is just `using16bit`.
* fix: cast Set16Bit inline arg to byte
