This allows to not use the internal game state directly from client
code.

Also make more state methods private.

* Implement move artifact action
* Fix widget update memory leak
  * update the highlights not during on each frame
  * do not update the unchanged label of a button
* Allow to exit the game by pressing 'q'
* Implement some cards from the magic set
* Improve permanent formatting
* Some tweaks to UnitAI code

adding area effects and hooks for permanents entering and leaving tiles

* Fix alot of bugs caused by permanents without tiles
* Implement a permanent choice to select the permanents in a pile
* Fix how pile hooks are called

* Introduce new callback for leaving a pile without beeing dropped
* Fix equipment contrsuctor
* Implement attack inheritance