add split by metadata to methods to get all permutations for stats
analysis
update test to match new method signature
Merge branch 'master' of https://github.com/mpi2/PhenotypeArchive.git

Conflicts:
	src/test/java/uk/ac/ebi/phenotype/stats/ObservationServiceTest.java
Merge branch 'master' of https://github.com/mpi2/PhenotypeArchive.git
always quote the metadata group
Merge branch 'master' of https://github.com/mpi2/PhenotypeArchive.git
export the custom exceptions in teh datamodel