* Added --token flag to swapcli's balances request allowing the user to query their token balance
* --eth-asset flag on swapcli make changed to --token
* Added TokenInfo RPC API method to retrieve an ERC20 token's metadata
* Added an end-to-end ERC20 unit test to the daemon package
* Fixed ERC20 token approval amount to SwapCreator contract to use the minimum value required (instead of approving the entire user's balance for transfer by the contract)
* Fixed a race condition between concurrent contract calls to approve/new_swap in ERC20 token swaps
* Removed hard coded assumptions that all tokens have 18 decimals
* Maked the decimal places in our test ERC20 token configurable
* Fixed token exchange rate calculations
* Updated ongoing and past swap queries to correctly support ERC20 tokens
* Initial unit tests in swapcli's main package
