- Implemented bidirectional transactions
- Added security: The player cannot change the transaction between its
  validation and its application because we duplicate it before
  validating it.

CHANGES ARE NOT TESTED YET.
First draft + task for today: "Pseudo-code of a round"
Finally we have to use some LLNCS latex model so no HTML output :(
Just another gitignore in this world
Multiple hours of fighting with LateX for MMD and then with LLNCS model. Still cannot make this citation thing to work without warnings but it looks it compiles + wrote a little abstract + a little [too little] intro + a handful of definitions.
More fighting with LateX (I think I hate LateX now) + Additional definitions + misc writing
Decision: Scheduled transaction have to happen _before_ the given time. They are checked at the _beginning_ of the rounds. Voting round description. Moved some details from definition to implementation / experimental setup.