Ali's changes to the ruby client

The diff is being pretty stupid about highlighting changes correctly, but my changes are:

Changing any references to 'doc' to use 'rdoc'. I think because the generateYard doc rake task wasn't working
* Adding rdoc to Gemfile
* Adding rdoc and /.idea to .gitignore 
* Updating rake with new RDoc task

Updates to the curl adapter
*  the request method already had an options hash parameter, I changed it so that it could accept arbitrary options as long as curb understands them. No checking, though
* Allowed get requests that include a body - appending it onto the url in the perform method
* Add extra return values from the request method. previously [curl.response_code, curl.body_str], now [curl.response_code, curl.body_str, curl.header_str, curl]. That's a little messy, but it doesn't cause a problem for existing code.
* Added a spec for the first item

First obvious question is why have these things in the ruby client? I need them for my test suite, but I'm just using my own repo anyway, so maybe we don't. On the other hand, why not?