This change adds the Template as a top level abstraction. URL templating
is now a two-stage process.
First you use a 'key' to look up a Template, then you use the Template
to create the URL.
This change also has some cleanup of the way RoutePatternBinder gets
instantiated. I added a factory service so that most of the complex
things can be made internal to Dispatcher. Now it's much easier to
constuct and use. These impacts some pubternal APIs that we already
broke, but makes them actually nice :)
Also cleaned up some tests and fixed one that was broken and not
running.
This makes endpoints and addresses easier to work with by dropping the
'metadata first' approach for the the things that are really at the core
of the dispatcher.
Ryan Nowak