Fixed bug; The update checker could in large installations take a few minutes to complete if statistics were shared; greatly improved the speed.
- Cause was processing within PHP of results from a complicated JOIN statement, which could better be done in separate queries.


git-svn-id: https://humgenprojects.lumc.nl/svn/LOVD3/trunk@472 a7477d18-a37e-46de-aef1-57953c184492