global: removal of `invenio_demosite` tests

* Removes left-over tests after `invenio_demosite`. (addresses #64)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
global: removal of SQL file and library receivers

* Removes further left-overs after `invenio-demosite`. (addresses #64)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
global: replacement of demosite by opendata

* Replaces "demosite" by "opendata".  (addresses #64)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
global: copyright message update

* Replaces "Invenio" by "CERN Open Data Portal" in copyright statements.
  (addresses #64)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
global: PEP-8 in copyright statements

* Uses one leading comment sign in copyright statements for better PEP-8
  compliance. (addresses #64)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
setup: cleanup of requirements

* Removes old packages from `requirements.txt'.  (addresses #64)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>