Remove global args from scriptclass

This commit removes all global args from the parameters of each function
on the scriptclass object, and updates all places they are called
accordingly. It also changes all instances of 'dwgfx' to 'graphics' in
Script.cpp.

Interestingly enough, it looks like editor.h depended on Script.h's
class define of the musicclass. I've temporarily placed the class define
in editor.h, but by the end of this patchset it'll be gone.

desktop_version/src/editor.cpp

@@ -4491,7 +4491,7 @@ void editorinput( KeyPoll& key, Graphics& dwgfx, Game& game, mapclass& map, enti
                         music.stopmusic();
                         dwgfx.backgrounddrawn=false;
                         ed.returneditoralpha = 1000; // Let's start it higher than 255 since it gets clamped
-                        script.startgamemode(21, key, dwgfx, game, map, obj, help, music);
+                        script.startgamemode(21);
                     }
                     //Return to game
                     //game.gamestate=GAMEMODE;