Altered:
- AMLightweightScanInfoCollection ~ Added the signal slot connections
for database change. All the code was already there, had just forgotten
to wire it all up (updates are tested, but inserts I can't
test till I have some time on the beamline)

- AMLightweightScanInfoCollection, AMLightweightScanInfoModel and
AMScanDataView ~ Altered the way ScanUrls are build from ModelIndices,
by simply querying the data() function of the index for the id, and
building from that. Fixes a bug where the loaded scan was determined
from it's row number, which was loading the wrong scans.