v0.6.0

Changelog

• Market functions fixed to pass through web3 args (#46)
• Approval reset param for simplifying optimal use of buy/sellOutcomeTokens (#47)
• Linting fixes (#48)
• Approval and buy/sell transactions now sent without waiting for approval tx to mine (#50)
• HumanFriendlyToken EIP20 extension interface added to contract abstractions available (#51)
• Can use subproviders instead of full providers as Web3 provider (#52)
• OlympiaToken exposed if on Rinkeby (#53)