Implements a mechanism by which search engines can provide different
result orderings, and implements a 'by location' ordering within the
Solr search engine (available whenever the user starts their search
from within a course or activity).
Introducing both APIs in moodle along with:
- search_box widget to add a tiny search box
- admin settings with setup steps helper
- cache for search results
- template for a search result
- php unit stuff
Many thanks to Tomasz Muras, Prateek Sachan and Daniel Neis for their contributions, for starting this development
and for pushing for it to be completed. Also thanks to other contributors: Jonathan Harker and eugeneventer.
