Update zmq.md
Update zmq.md

Typo fixes and update python to python3 in sample commands

Darknet-Crypto/Darknet,PIVX-Project/PIVX,PIVX-Project/PIVX,npccoin/npccoin,Mrs-X/PIVX,PIVX-Project/PIVX,Darknet-Crypto/Darknet,Darknet-Crypto/Darknet,npccoin/npccoin,PIVX-Project/PIVX,npccoin/npccoin,Mrs-X/PIVX,PIVX-Project/PIVX,Darknet-Crypto/Darknet,PIVX-Project/PIVX,PIVX-Project/PIVX,Mrs-X/Darknet,Mrs-X/PIVX,Mrs-X/Darknet,Darknet-Crypto/Darknet,Mrs-X/Darknet,Mrs-X/PIVX,Mrs-X/Darknet,Mrs-X/Darknet,Darknet-Crypto/Darknet,Mrs-X/PIVX,PIVX-Project/PIVX,npccoin/npccoin,PIVX-Project/PIVX,npccoin/npccoin,Mrs-X/PIVX,Mrs-X/Darknet,npccoin/npccoin