Split up files so that the scenario editor will build

- cCreature split into seperate file-pair from cMonster/cTownperson
- fileio.cpp split into general, party, and scenario sections
- classes.h file deleted

src/scenedit/scen.fileio.cpp

@@ -1,7 +1,7 @@
 
 #include <cstring>
 #include "scen.global.h"
-#include "classes.h"
+#include "scenario.h"
 #include <iostream>
 #include <fstream>
 #include <iomanip>