Don't use named graphs: data-manager

Triples from driver instances now go into default graph and tracked
using reified statements.
Remove use of named graphs in queries
Add filter for fetching driver instances
Updated data-manager

Fixed sparql bugs
Merge remote-tracking branch 'origin/master' into reification
Update toNT for sparql bindings
Updated data-manager

Updated clearing and deleting graphs to not use named graphs.