Adding some instructions for using the sim, also improving the --help

output to be more consistent

README.md

@@ -103,11 +103,11 @@ Build host tools only:
 docker run --rm -v $(pwd):/workspace rtlplayground-dev make -C tools
 ```
 
-Run the web-interface simulator locally:
+Run the web-interface simulator through docker:
 
 ```
-docker run --rm -p 8080:8080 -v $(pwd):/workspace rtlplayground-dev \
-  tools/output/httpd_sim /workspace/html
+docker run --rm -p 8081:8081 -v $(pwd):/workspace rtlplayground-dev \
+  tools/output/httpd_sim.py /workspace/html
 ```
 
 Edit `config.txt` on your host, then re-run `make` — the
@@ -362,7 +362,31 @@ session xxxx            = Web session timeout in seconds (default 200)
 
 Enjoy playing!
 
-## (11) Other documents
+## (13) HTTP Simulator for front-end development
+
+The simulator is available in tools as `./httpd_sim.py`
+By default it will serve the content in the current working directory so the easiest way to run this is to:
+```
+cd ./html
+../tools/httpd_sim.py
+```
+And the simulator will be available on http://127.0.0.1:8081
+
+There are commandline options available:
+```
+usage: httpd_sim.py [-h] [--machine MACHINE] [--port PORT] [--bindaddr BINDADDR] [--verbose]
+
+options:
+  -h, --help           show this help message and exit
+  --machine MACHINE    path to machine.c or .h file to parse (optional)
+  --port PORT          port to bind to (default 8081)
+  --bindaddr BINDADDR  address to bind (default 127.0.0.1)
+  --verbose            enable verbose output
+```
+
+The machine parsing is somewhat experimental.
+
+## (12) Other documents
 
 The following documents give further documentation on specific features of the RTL837x SoCs:
 - [Adding a new device](doc/adding-a-device.md)