⇋ v0.3.1

New

• Now, You can build Normal Transaction for all cryptocurrencies, swap.providers.cryptocurrency.transaction.NotmalTransaction class.
• Add MAX-Amount withdraw/refund parameter option for all Claim Transaction and Refund Transaction classes.

Improvements

• When building Claim and Refund transactions the fee is paid from Recipient/Sender account but now it's changed into paid from HTLC contaract for both Bytom and Vapor providers.
• All amout unit converter function name changed from amount_converter to amount_unit_converter function.