introduce Makefile
add two test cases on rest_freeze_amount
introduce build_balance* methods in Order
add test on build_balance_diff_for_create
add test for build_balance_diff_for_close
add a check on balance_diff.new_active and .new_frozen
add pybloomfiltermmap to requirements.txt
take pybloom instead of pybloomfiltermmap
add TestOrder
introduce test for AccountCreated and AccountCanceled
add test for credit then cancel