Daddy32: Tasks Mode

Gives the user the opportunity to earn some credits for performing various tasks.

Known bugs removed, tested stability-wise, not so much game-wise.
Lots of to-dos and ideas still remaining, better balance between task difficulty and their rewards needed - please comment.

Usage:
Enter shop, open menu, select 'See available tasks'.
All tasks in the list are active, until they expire ('Days left'; day passes after each duel (won, lost or quited)).
You can finish any of the tasks and get bonus. For particular task, the bonus gets a bit smaller every day (until expiration).

projects/mtg/src/GameObserver.cpp

@@ -209,6 +209,9 @@ void GameObserver::startGame(Rules * rules){
     }
   }
 
+  startedAt = time(0);
+
+
   //Difficult mode special stuff
   if (!players[0]->isAI() && players[1]->isAI()){
     int difficulty = options[Options::DIFFICULTY].number;