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.core.cpp

@@ -5,7 +5,8 @@
 #include <numeric>
 #include <boost/lexical_cast.hpp>
 #include "scen.global.h"
-#include "classes.h"
+#include "scenario.h"
+#include "regtown.h"
 #include "graphtool.hpp"
 #include "scen.graphics.h"
 #include "scen.core.h"