Fix Monav routing message generation

Such a stupid mistake. :P Looks like I wanted to finally add the localisation support for routing messages, but stopped in the middle of working on it and committed the half-finished code.
So as a result, the routing messages not only were not translated, but were all None. :)
Lock the task tracking dictionary when it is being read or written

So that items don̈́t suddenly vanish when it is being drawn to screen and there are no "dictionary changed during iteration" errors.