Zandronum config migrator

This python script migrates server .cfg files. Zandronum 2.0 moved the bits of dmflags around due to the upgrade to ZDoom 2.5, so any server configs using anything like dmflags 1234567 and the like will end up with bad settings.

This script calculates the corrected dmflags values and edits configs in-place, appending corrected dmflag settings (along with information about what was changed). The old values are left in!

To use, run it as python <config> [config] [config...].