bip32: adds network option for bitcoin addresses
++ identity (hash160 public-key)
++ fingerprint (cut 3 [16 4] identity)
::
+++ address
+ |= network=?(%main %regtest %testnet)
+ ^- @uc
+ :: removes checksum
+ ::
+ %^ rsh 3 4
+ %+ en-base58check
+ [4 (version-bytes network %pub %.n)]
+ [20 identity]
+::
++ prv-extended
|= network=?(%main %regtest %testnet)
%+ en-b58c-bip32 (version-bytes network %prv %.y)
