Update README

Change Ubuntu version order

Author: kojix2

README.md

@@ -19,29 +19,28 @@ We recommend the [Pry](https://github.com/pry/pry) backend for full functionalit
 ### Ubuntu
 Install Jupyter with [Anaconda](https://www.anaconda.com/) (recommended).
 
-#### Setup ZeroMQ on Ubuntu 16.04
-CZTop requires CZMQ >= 4.0.0 and ZMQ >= 4.2.0. The official packages for Ubuntu 16.04 don't satisfy these version requrements, so you need to install from source.
+#### 17.04 to 19.04
 
 ```shell
 sudo apt install libtool libffi-dev ruby ruby-dev make
-sudo apt install git libzmq-dev autoconf pkg-config
-git clone https://github.com/zeromq/czmq
-cd czmq
-./autogen.sh && ./configure && sudo make && sudo make install
+sudo apt install libzmq3-dev libczmq-dev
 
-gem install cztop
+gem install ffi-rzmq
 gem install iruby --pre
 iruby register --force
 ```
 
-#### Setup ZeroMQ on Ubuntu 17.04 to 19.04
-Use official packages.
+#### 16.04
+CZTop requires CZMQ >= 4.0.0 and ZMQ >= 4.2.0. The official packages for Ubuntu 16.04 don't satisfy these version requrements, so you need to install from source.
 
 ```shell
 sudo apt install libtool libffi-dev ruby ruby-dev make
-sudo apt install libzmq3-dev libczmq-dev
+sudo apt install git libzmq-dev autoconf pkg-config
+git clone https://github.com/zeromq/czmq
+cd czmq
+./autogen.sh && ./configure && sudo make && sudo make install
 
-gem install ffi-rzmq
+gem install cztop
 gem install iruby --pre
 iruby register --force
 ```