Various field/belt related stuff

- Remove all field booleans except quickfire and belt, which have been moved to cCurTown
- Alter and extend place_spell_pattern, to allow arbitrary damage types and to make it more clear in the code what's happening when it's called
- Delete fields.cpp file; a few things moved to locutils.cpp, but most are now part of cCurTown
- set_terrain function automatically updates belt present boolean if setting to a conveyor.

osx/boe.global.h

@@ -1,6 +1,7 @@
 
-#ifndef BOE_GLOBAL_H
-#define BOE_GLOBAL_H
+
+#ifndef BOE_GAME_GLOBAL_H
+#define BOE_GAME_GLOBAL_H
 
 #include <vector>
 #include <string>
@@ -62,7 +63,7 @@ public:
 };
 
 struct effect_pat_type {
-	unsigned char pattern[9][9];
+	unsigned short pattern[9][9];
 };
 
 #endif