Add support for BitcoinCash test network prefix

[attikos]

Hi!
Can add support BitcoinCash format with prefix bchtest:: bchtest:pp92lyy7qguahkudxvjxhfg0zn8vfp6syy84fyza6u
It works fine without a prefix: pp92lyy7qguahkudxvjxhfg0zn8vfp6syy84fyza6u

I checked 'test' and 'both' of the networkType.
Test address: https://explorer.bitcoin.com/tbch/address/2Mz48JwfRr1HhMgn6M5BpwTJEB13GrEgZzt

Thanks!

[tillkolter]

#49