Finish Character Saving/Loading

- Finish adding loading character data
- Add an option to clear the current character data slot
- Add a simple checksum check for ZDoom™-proofing
- If a load goes wrong, try to inform the player of roughly what happened
- Save/Load messages are logged and stick around longer so the new subtext can
  be read
Merge branch 'master' of https://github.com/Kyle873/DoomRPG

Conflicts:
	DoomRPG/acs/RPG.lib