Add an option for sending destination eth address in an OP_RETURN output

[oscarguindzberg]

Reading public key from first tx input

• Hardware wallet unfriendly on eth side
• Have to extract private key from doge and copy to eth wallet
• Have to add some eth to the account to pay for gas. Users would use that account just use for the doge-eth bridge, so adding some eth there is a nuissance.

Using OP_RETURN

• Have to develop a special program to build the doge tx.
• Users have install/use that program instead of the standard wallet they are used to (dogecoin-qt or some other wallet)