New version of search field + misc.

- Changed field selector + search field into single
  search field containing icons for syntax help, clear, and search options.
  (This is currently a proof-of-concept so much of it is static data and
  inline styles that need to be cleaned up when we have landed on something
  we want to keep)
- Added image-based gradient and drop-shadow to header to make it appear like
  on the DTU web site.
- Adjusted cukes and steps to handle new search field.
- Fixed responsive issues to make header work for different sizes (this still
  needs finetuning to make it look better).
- Formatting of hit counts and facet counts using delimiters.
- Changed some labels.
- Temporarily removed display of active search constraints. These are to be moved
  elsewhere.
- Removed grey boxes from top of search result. Some of the content from those
  are to be placed elsewhere and some of it is to be left out.