Issue #307: fix API regresssions

- allow strings with dots in router script for API calls
- escape slashes  when searching for an entity
- fix perfect_match search on string search returning no result
- adapt dev server script to run outside of the web folder (needed to allow dots in urls)
- change dev server port to 8082 (less likely to collide with another instance)
- redirects of API searches without a repo fallback to 'release' repository to not fail (no cookie to read with the api)
- updated README
Do we want to fallback to 'strings' in case it's missing? I think Matjaz reported a problem with that.