getRequestForVersions
Request to get summary information about each Salesforce.com version currently available.
Return
RestRequest object that requests the list of versions.
See also
<a href="http://www.salesforce.com/us/developer/docs/api_rest/Content/resources_versions.htm">http://www.salesforce.com/us/developer/docs/api_rest/Content/resources_versions.htm</a>