Update zmq.md

Typo fixes and update python to python3 in sample commands

doc/zmq.md

@@ -1,4 +1,4 @@
-# Block and Transaction Broadcasting With ZeroMQ
+# Block and Transaction Broadcasting with ZeroMQ
 
 [ZeroMQ](http://zeromq.org/) is a lightweight wrapper around TCP
 connections, inter-process communication, and shared-memory,
@@ -33,12 +33,14 @@ buffering or reassembly.
 
 ## Prerequisites
 
-The ZeroMQ feature in PIVX Core requires ZeroMQ API version 4.x or
-newer. Typically, it is packaged by distributions as something like
+The ZeroMQ feature in PIVX Core requires the ZeroMQ API >= 4.0.0
+[libzmq](https://github.com/zeromq/libzmq/releases).
+For version information, see [dependencies.md](dependencies.md).
+Typically, it is packaged by distributions as something like
 *libzmq3-dev*. The C++ wrapper for ZeroMQ is *not* needed.
 
 In order to run the example Python client scripts in contrib/ one must
-also install *python-zmq*, though this is not necessary for daemon
+also install *python3-zmq*, though this is not necessary for daemon
 operation.
 
 ## Enabling
@@ -50,7 +52,7 @@ during the *configure* step of building pivxd:
     $ ./configure --disable-zmq (other options)
 
 To actually enable operation, one must set the appropriate options on
-the commandline or in the configuration file.
+the command line or in the configuration file.
 
 ## Usage
 
@@ -103,6 +105,6 @@ and just the tip will be notified. It is up to the subscriber to
 retrieve the chain from the last known block to the new tip.
 
 There are several possibilities that ZMQ notification can get lost
-during transmission depending on the communication type your are
-using. PIVXd appends an up-counting sequence number to each
+during transmission depending on the communication type you are
+using. pivxd appends an up-counting sequence number to each
 notification which allows listeners to detect lost notifications.