Added a warning check before doing destructive operations (make remove-demo-records, make drop-demo-site, make drop-tables). Knowledgeable people can use "FORCE=yes make drop-tables" to bypass the check.  Added deletion of fulltext files when removing demo records.
Added a warning check before doing destructive operations (make
remove-demo-records, make drop-demo-site, make drop-tables).
Knowledgeable people can use "FORCE=yes make drop-tables" to bypass
the check.  Added deletion of fulltext files when removing demo
records.

inveniosoftware/invenio,inveniosoftware/invenio,tiborsimko/invenio,tiborsimko/invenio