Angular tmpl-engine: Fix suggested id

SS currently produces template ids with a dash instead of a path separator.
When referencing a template in `<projectRoot>/client/templates/foo/bar.html`, the SS angular engine will create the id `foo-bar.html`.

In angular world people use actual path-like ids, so the above use case would lead angular devs to use  `foo/bar.html` in their directives & views.

Attached code will allow guys to not switch to another convention when working with SS.