(TK-58) Add remaining default server support

Add default server support to the `override-webserver-settings!`,
`get-registered-endpoints`, `log-registered-endpoints`, and
`join` service functions.
(TK-52) Remove default endpoint requirement

Remove the requirement that an endpoint with id of `:default`
be present in a multi-route configuration from the webrouting
service.
(TK-52) Require route-id with multiroute configs

Stop honoring the :default route in a multi-route config. Now,
a route-id is required whenever an operation is performed.
(TK-52) Move variable out of let statement

Move the no-route-multi? variable out of the let statement
containing it and put its value directly into the cond statement.
Merge pull request #60 from fpringvaldsen/TK-52-remove-default-endpoint-requirement

(TK-52) Remove default endpoint requirement
Merge pull request #63 from fpringvaldsen/TK-58-more-default-support

(TK-58) Add remaining default server support