Remove semi-useless function editorclass::weirdloadthing()

Looks like this function was created because editorclass::load() takes
in a string by reference, not by value, and thus mutates it afterwards,
so if you passed a string in when you didn't want it to be mutated, bad
things would happen.

However, a better workaround for the above issue would simply to
duplicate the string and pass that string instead, thus the original
string wouldn't be affected.

desktop_version/src/Script.cpp

@@ -3221,9 +3221,11 @@ void scriptclass::startgamemode( int t )
 		//load("intro");
 		break;
   case 22:  //play custom level (in game)
+  {
     //Initilise the level
     //First up, find the start point
-    ed.weirdloadthing(ed.ListOfMetaData[game.playcustomlevel].filename);
+    std::string filename = std::string(ed.ListOfMetaData[game.playcustomlevel].filename);
+    ed.load(filename);
     ed.findstartpoint();
 
     game.gamestate = GAMEMODE;
@@ -3263,10 +3265,13 @@ void scriptclass::startgamemode( int t )
 		graphics.fademode = 4;
     //load("intro");
   break;
+  }
   case 23: //Continue in custom level
+  {
       //Initilise the level
     //First up, find the start point
-    ed.weirdloadthing(ed.ListOfMetaData[game.playcustomlevel].filename);
+    std::string filename = std::string(ed.ListOfMetaData[game.playcustomlevel].filename);
+    ed.load(filename);
     ed.findstartpoint();
 
     game.gamestate = GAMEMODE;
@@ -3309,6 +3314,7 @@ void scriptclass::startgamemode( int t )
 		graphics.fademode = 4;
     //load("intro");
   break;
+  }
 #endif
 	case 100:
 		game.savestats();