WebSearch: fix case-insensitive collection search
WebSearch: fix case-insensitive collection search

* Before checking if a record is in the reclist of a collection,
  check if the collection actually exists and normalise its
  name from case-insensitive to case-sensitive. (fixes #530)

* When trying to guess the collection of a record from the
  referer URL, test if this referer comes from the same Invenio
  installation, since URLs are similar in different installations.

inveniosoftware/invenio-search,tiborsimko/invenio-search,tiborsimko/invenio-records,inveniosoftware/invenio-search,tiborsimko/invenio-records,inveniosoftware/invenio-records,tiborsimko/invenio-search,inveniosoftware/invenio-records