Display additional parameter options

Just to discuss. 

rspec_api_documentation already exports additional parameter options to JSON, so we can easily display them. Not sure about all options, but *default* seems very reasonable to me.

What do you think?

![screen shot 2013-06-04 at 10 41 45 pm](https://f.cloud.github.com/assets/186223/606166/24bd4f2a-cd25-11e2-9c93-00d5bac58fcc.png)

![screen shot 2013-06-04 at 10 40 45 pm](https://f.cloud.github.com/assets/186223/606167/2ccbf04a-cd25-11e2-9828-49be8f46a560.png)