Implemented Emperor Cobra and fixed a bug in event ordering

did_damage was not being triggered if the minion was removed from the
board.
Implemented Patient Assassin
flake8 fixes
Fixes for Emperor Cobra

The fixes include that the poisonous effect shouldn't kill the hero. And
that silence removes the effect.
And renamed the def to poisonous, like the mechanic in Hearthstone.
Implemented SI:7 Agent

This commit marks rogue minions as complete.
Implemented Assassinate
Implemented Betrayal
Implemented Blade Flurry
Implemented bounce()

bounce() removes a minion from the board and places it in its owner's hand
Implemented Freezing Trap
Fix for bounce()
Added a trigger for card destruction when bounced with too many cards in hand
Added a removed property to Character

This property allows attack() to detect if an attacker was removed mid attack
Additional testing of Freezing Trap with the max number of cards in hand
Removed redundant check for death
A fix to apply auras to health after a minion is played
Implemented Crazed Alchemist
Fix for bounce (minions die when the hand is too full)

Previously, the card was destroyed.
Merge branch 'master' of https://github.com/danielyule/hearthstone-simulator

Conflicts:
	hsgame/cards/minions/__init__.py
	hsgame/cards/minions/neutral.py
	tests/card_tests/neutral_tests.py