change safeguards
fix /0
threshold optim
Merge branch 'master' of ssh.biais.org:bitcoin-arbitrage

Conflicts:
	src/observers/specializedtraderbot.py
Fix emailer and catch mtgox exception

Conflicts:
	src/observers/emailer.py
	src/private_markets/mtgox.py
fix error when no bids or asks exists in market

Conflicts:
	src/arbitrage.py
Add widthdraw and deposit method to transfer btc between exchange place

Conflicts:
	src/private_markets/bitcoincentral.py
	src/private_markets/mtgox.py