- items in group -> files not being found if they are not attached to
a view

- added code so that unattached group artefacts can be checked against
the artefact_access_role table (currently only used for group
artefacts) to see what roles they can be viewed by

Change-Id: I17eb03241e10e44460c0596c3d982c00dd39f336
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>