Add testnet version bytes

Author: clarkmoody

bip-0084.mediawiki

@@ -54,7 +54,7 @@ To derive the P2WPKH address from the above calculated public key, we use the en
 
 ===Extended Key Version===
 
-When serializing extended keys, this scheme uses alternate version bytes. Extended public keys use <code>0x04b24746</code> to produce a "zpub" prefix, and private keys use <code>0x04b2430c</code> to produce a "zprv" prefix.
+When serializing extended keys, this scheme uses alternate version bytes. Extended public keys use <code>0x04b24746</code> to produce a "zpub" prefix, and private keys use <code>0x04b2430c</code> to produce a "zprv" prefix. Testnet uses <code>0x045f1cf6</code> "vpub" and <code>0x045f18bc</code> "vprv."
 
 
 ==Backwards Compatibility==