Add documentation for network simulator

docs/source/index.rst

@@ -71,6 +71,7 @@ Read on to learn:
 
    release-process
    release-notes
+   network-simulator
    codestyle
    building-the-docs
 

docs/source/network-simulator.rst

@@ -0,0 +1,41 @@
+Network Simulator
+=================
+
+A network simulator is provided which shows traffic between nodes through the lifecycle of an interest rate swap
+contract. It can optionally also show network setup, during which nodes register themselves with the network
+map service and are notified of the changes to the map. The network simulator is run from the command line via Gradle:
+
+**Windows**::
+
+    gradlew.bat network-simulator:run
+
+**Other**::
+
+    ./gradlew network-simulator:run
+
+Interface
+---------
+
+.. image:: network-simulator.png
+
+The network simulator can be run automatically, or stepped manually through each step of the interest rate swap. The
+options on the simulator window are:
+
+Simulate initialisation
+  If checked, the nodes registering with the network map is shown. Normally this setup step
+  is not shown, but may be of interest to understand the details of node discovery.
+Run
+  Runs the network simulation in automatic mode, in which it progresses each step on a timed basis. Once running,
+  the simulation can be paused in order to manually progress it, or reset.
+Next
+  Manually progress the simulation to the next step.
+Reset
+  Reset the simulation (only available when paused).
+Map/Circle
+  How the nodes are shown, by default nodes are rendered on a world map, but alternatively they can rendered
+  in a circle layout.
+
+While the simulation runs, details of the steps currently being executed are shown in a sidebar on the left hand side
+of the window.
+
+.. TODO: Add documentation on how to use with different contracts for testing/debugging