Add 0xBTC Mineable Token Currency

You should add support for 0xBTC token (largest mined token), like Opensea does. That way 0xBTC art like this can be traded with it:

https://0xbitcoin.org/#/

0xb6ed7644c69416d67b522e20bc294a9a9b405b31

This will be the only mined currency on the platform after Eth PoS :smiley: