add '_routes' generating macro

Difference between Erlang and Elixir controller is in '_routes' functions, that would be generated. This commit will extend macro for generating '_routes' function for Elixir controller too.

Open question is, that this macro doesn't support '_routes' generation from a def definitions.

There are too possible solutions:
Add syntax without explicit like:
defa index(req, session_id, :GET, []) ...
defaction index(req, session_id, :GET, []) ...

Or make it working with def definitions.