CodeParser: Call ProcessCodeList_int() in the opcode macros.

Calling ProcessCodeList() restarts the regnum counter, which will
break anything that uses registers.
CodeParser: Convert to a regular class.

CodeParser now contains both the code list and register vector.
The list can be fully reloaded at any time via filename or istream.

New clear() function to clear the code list and register vector.
The register vector wasn't actually properly deleted before, since
it has new'd memory buffers. This usually isn't a problem, since
the code list is typically loaded once and kept in memory until
the program exits.

dllmain.cpp: Updated to use CodeParser as a regular class,
and eliminated a goto.