Clean up and prevent unnecessary qualifiers to self

By "unnecessary qualifiers to self", I mean something like using the
'game.' qualifier for a variable on the Game class when you're inside a
function on the Game class itself. This patch is to enforce consistency
as most of the code doesn't have these unnecessary qualifiers.

To prevent further unnecessary qualifiers to self, I made it so the
extern in each header file can be omitted by using a define. That way,
if someone writes something referring to 'game.' on a Game function,
there will be a compile error.

However, if you really need to have a reference to the global name, and
you're within the same .cpp file as the implementation of that object,
you can just do the extern at the function-level. A good example of this
is editorinput()/editorrender()/editorlogic() in editor.cpp. In my
opinion, they should probably be split off into their own separate file
because editor.cpp is getting way too big, but this will do for now.

desktop_version/src/Entity.h

@@ -10,8 +10,22 @@
 #include "BlockV.h"
 #include "Game.h"
 
-#define removeentity_iter(index) { if (obj.removeentity(index)) index--; }
-#define removeblock_iter(index) { obj.removeblock(index); index--; }
+#define removeentity_iter(index) \
+    do \
+    { \
+        extern entityclass obj; \
+        if (obj.removeentity(index)) \
+        { \
+            index--; \
+        } \
+    } while (false)
+#define removeblock_iter(index) \
+    do \
+    { \
+        extern entityclass obj; \
+        obj.removeblock(index); \
+        index--; \
+    } while (false)
 
 enum
 {
@@ -193,6 +207,8 @@ public:
     bool customcrewmoods[Game::numcrew];
 };
 
+#ifndef OBJ_DEFINITION
 extern entityclass obj;
+#endif
 
 #endif /* ENTITY_H */