Put /tc map on the main thread

This change was already made on the BiomeGroups branch. This should make
the biome mapper more reliable on the main branch too, at the cost of
pausing the server for a while.

Author: rutgerkok

platforms/bukkit/src/main/java/com/khorn/terraincontrol/bukkit/commands/MapCommand.java

@@ -111,7 +111,7 @@ public boolean onCommand(CommandSender sender, List<String> args)
 
         MapWriter map = new MapWriter(world.getHandle(), size, angle, sender, offsetX, offsetZ, label);
 
-        this.plugin.getServer().getScheduler().runTaskAsynchronously(this.plugin, map);
+        this.plugin.getServer().getScheduler().runTask(this.plugin, map);
 
         return true;
     }