Refactor PRF_gadget to hand responsibility to PRF_addr_a_pk_gadget for creating the '0' argument to the PRF.
Refactor PRF_gadget to hand responsibility to PRF_addr_a_pk_gadget for creating the '0' argument to the PRF.

aniemerg/zcash,CTRoundTable/Encrypted.Cash,bitcoinsSG/zcash,CTRoundTable/Encrypted.Cash,bitcoinsSG/zcash,bitcoinsSG/zcash,aniemerg/zcash,CTRoundTable/Encrypted.Cash,CTRoundTable/Encrypted.Cash,CTRoundTable/Encrypted.Cash,aniemerg/zcash,aniemerg/zcash,CTRoundTable/Encrypted.Cash,bitcoinsSG/zcash,bitcoinsSG/zcash,aniemerg/zcash,aniemerg/zcash,bitcoinsSG/zcash