Add helpers object which includes query string binder for DateTime

If DateTime objects are used for query parameters, the user currently has to
write their own binders to parse the string. Importing
${ssd.packageName}.helpers._ will provide useful implementations.
e.g.
PlayKeys.routesImport += "referenceapi.helpers._"
Merge pull request #62 from fiadliel/wip/bindable-helpers-for-datetime

Add helpers object which includes query string/path binders for DateTime

If I add a "date-time-iso8601" query parameter like this:

{
  "method": "GET",
  "parameters": [
    { "name": "since", "type": "date-time-iso8601", "required": false }
  ]
}
then the resulting route will look like:
GET /xxx controllers.Xxx.get(since: Option[org.joda.time.DateTime])

users can import this helper to parse data time parameters
Ruby Client: Only generate accessors for resources (not models)

 - Fixes #90
Introduce operation body
Make sure no path parameters are mixed with bodies
Validate that body is not supported for GET/DELETE
Work in progress on play client generation for bodies
Further along in adding body to scala client
Add query strings to all method calls
Working support in play client for form bodies along with query parameters
Fix bug with enumerations in ruby client - cannot instantiate values until full client is loaded
Update spec for ruby client enum support
Add support for query params to all requests types in ruby client.
Add body support to ruby client, including serialization to json from model classes
Fully qualify model class name
Update release notes
Update api.json schema with definition of bodies
Fix typo
Merge pull request #94 from gilt/issue-19-bodies

Add support for "body" element to explicitly specify type of form body in an operation

Introduce 'body' on operations. For operations that support posting data, you can now specify a 'body' for the JSON document instead of explicit parameters. The body parameter takes a single attribute - type - specifying the name of a model.

Bodies and query parameters are now fully supported in the play 2.3 client and the ruby client.

Query parameter support for operations. When specifying a body, you can also specify additional query parameters for an operation. The parameters section of operations is now interpreted as being in the body by default, and if a 'body' element is provided, the parameters are expected to be sent as query parameters.
Update unit tests per latest changes to ruby enums