request-uri wouldn't resolve path parameters

[kamituel]

Example:

[["users"] 'example.users
     [[:user-id "friends"] 'example.friends]]

Then, in a handler in `example.friends, the :resource-uri would be something like /users/:user-id/friends, while I'd expect /users/100/friends.

[hlship]

I'm reworking a bunch of the dispatcher code now, to make this easier to fix.