Add a Quick start section to the README

I can never remember what value I'm supposed to use for the endpoint when I want to use Mimic. Having a curl and OpenStack CLI example shows the proper value for OS_AUTH_URL settings and how to see the service catalog to get a list of other product-specific endpoints.
Ha - I never noticed that. Probably because I was piping things through `python -m json.tool`

Could you make it log that when the server starts up, i.e. right after:
```
2014-11-14 16:31:12-0500 [-] Site starting on 8900
2014-11-14 16:31:12-0500 [-] Starting factory <twisted.web.server.Site instance at 0x10ec6bea8>
```

I also tried to see if twistd/klein has the ability to do something like [rake routes](http://stackoverflow.com/questions/6826166/understanding-rake-routes-output) but I haven't found anything.