Add measurement of wall clock time to weighted queries
Add measurement of wall clock time to weighted queries

ES performance on weighted queries was reported in the time spend by
ES. Added measurement of wall clock time.

UUDigitalHumanitieslab/texcavator,msassmann/texcavator,UUDigitalHumanitieslab/texcavator,msassmann/texcavator,msassmann/texcavator,msassmann/texcavator,UUDigitalHumanitieslab/texcavator