KNOWN BUGS

- all quest-related issues have a problem with more than one hero in the stack

- Attacking a stack, loosing the fight and creating a level advancement situation
    somehow seems to lock the game in an endless loop.

- When two Ai players fight each other, the game crashes on a win
    The game is finished, but the AI player keeps looking for cities

- the function for loading a map in the GamePreferences is unintuitive. Improve it

- fix RAddUnit (see class description in RAddUnit.h for explanation)

- when the tileset is loaded twice, the tiles are black. Fix it!

- sometimes there are font problems. Take the new font from paragui 1.0.4.
    Update: Propably a rare bug in the combination paragui/libfreetype
    Update2: not so rare

BUGS TO BE VERYFIED

- when you exit at the correct time, the bigmap timer will be raised, leading
to a segfault
    Update: When destroying bigmap, I have inserted a sleep. Is not the perfect
    solution, but should prevent the race condition. Besides, the blitting done
    by the bigmap should consume a lot less time now.

- the game occasionally crashes on exit
    Update: looks like this has gone, but I don't really now why.
