fixed logical issue in simulation

previously allowed active_player to rethink an action with information
they couldnt have known (valid_blocks).  If it gets to valid_blocks, its
for BlockedAction not RethinkAction
changed main simulation loop drastically

mainloop now iterates players rather than range() and all instances
involving the index position removed.

selecting an opponent now happens during the beginning of every turn as
it doubles as whether the active_player is the last man standing when it
excepts.
Merge remote-tracking branch 'origin/master' into pybrain
trained supervision tuning