WebSearch: show full-text snippets
WebSearch: show full-text snippets

* Show full-text snippets for full-text searches around the seeked
  pattern.  Initial simple version, not yet activated by default
  in the stock invenio.conf.

* Beware, assuming that we can display any full-text file snippets
  to the users if they have right to see the metadata record.

inveniosoftware/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,tiborsimko/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter