WebSearch: rename Fulltext tab to Files tab
WebSearch: rename Fulltext tab to Files tab

* Rename Fulltext tab to Files tab, as it contains any attached files.
  (closes #360)

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