Fix an error in docs, and align some code
Implement market order functionality
Merge pull request #38 from davemarchevsky/market_order

Implement market order functionality
Merge pull request #36 from knewter/doc_typofix

Fix an error in docs, and align some code
Merge remote-tracking branch 'upstream/master' into feature/make_client_instances
Fix tests that were added since this feature branched