use set instead of hashset
use different control strategy (use concurrent controls if available,
else use all results (don't limit by time);
Refactor to remove redundant phenotypingCenter string variable from
observation method
Merge branch 'master' of https://github.com/mpi2/PhenotypeArchive.git

Conflicts:
	src/main/java/uk/ac/ebi/phenotype/stats/ObservationService.java

	manually merged
Merge branch 'master' of https://github.com/mpi2/PhenotypeArchive.git