Updated the SyndicationServlet to provide an additional option to return details of the tags in the repository instead of the commits.
This uses a new 'ot' request parameter to indicate the object type of the content to return, which can be ither TAG or COMMIT.
If this is not provided, then COMMIT is assumed to maintain backwards compatability.
If tags are returned, then the paging parameters, 'l' and 'pg' are still supported, but searching options are currently ignored.
Change enum name and unit test RSS tag queries
Merged #66 "Query tags using RSS feeds"