Remove unnecessary middleman ed.swapmap

When the game loads a room in a custom level, previously it would load
the tilemap of that room into ed.swapmap, and then mapclass::loadlevel()
would manually go through each element in ed.swapmap to set each tile in
`contents`. Why do that, when you can just return the vector from
editorclass::loadlevel() and set it directly? ed.swapmap is really
unnecessary.

desktop_version/src/Map.cpp

@@ -1568,18 +1568,12 @@ void mapclass::loadlevel(int rx, int ry)
 			roomname=ed.level[curlevel].roomname;
 		}
 		extrarow = 1;
-		ed.loadlevel(rx, ry);
+		contents = ed.loadlevel(rx, ry);
 
 
 		roomtexton = false;
 		roomtext.clear();
 
-		for (int edj = 0; edj < 30; edj++){
-			for(int edi = 0; edi < 40; edi++){
-			contents[edi + vmult[edj]] = ed.swapmap[edi + vmult[edj]];
-			}
-		}
-
 		//Entities have to be created HERE, akwardly
 		int tempcheckpoints=0;
 		int tempscriptbox=0;