add invisible hand
Merge remote-tracking branch 'origin/corporations' into invisible-hand
add invisible_hand tests
add test to invisible hand
update invisible hand task
Merge pull request #6 from Neamar/invisible-hand

Invisible market hand
rename TEsts to tests
tests in invisible hand now work
tests in invisible hand now really work
Only buy influence once per turn
Check orders cost in engine
Store cost in DB
Check order cost do not exceed player money
Merge branch 'master' into share

Conflicts:
	corporate/settings.py
Limit influence buys