Add readme and log info message with url where the tool is running

[jhrcek]

Nice tool. I learned about it from elm-newsletter :-)
I think it would be good to add basic usage instructions to readme (in particular I had to browse the source code to find it's running on port 4040). It would also be good to log the info with url where the tool is running, so it can be quickly navigated to from terminal.

[zwilias]

Published as 0.0.2, together with a --help flag, auto-open-a-browser functionality and the possibility to override the port using --port!