fix bug in mySQL WHERE clause for mrefs
Merge pull request #1691 from jjettenn/feature/simplified_filter_UX_2649

Complex filters simple UX select2 results
Merge pull request #1692 from bartcharbon/master

fix bug in mySQL WHERE clause for mrefs
Fix for the problem where when an operator is shown for the filter query
Fix a problem simple filters are not positioned correctly
Fix problem retrieving xref mref with lookup attributes instead of
unique attributes
Merge branch 'master' of github.com:molgenis/molgenis into feature/simplified_filter_UX_2649