expose data types of highdim fields
Fix tests

Rather than specifying the returned types by hand for AllDataProjection.rowProperties and MultiValueProjection.dataProperties,
they are reflectively taken from the appropriate classes.

Also fix a small bug in the metabolomics test data where the 'intensity' field would always be null.
Merge pull request #39 from thehyve/refactor/optimize_protobuf

Refactor/optimize protobuf