support formula cells, add tests
small bug fixes for last commit
add exception message in case of invalid values
fix csv add command (use simple instead of full entity class name)
Merge branch 'testing' of https://github.com/molgenis/molgenis into testing
Merge branch 'testing' of https://github.com/molgenis/molgenis into testing
Merge pull request #198 from dennishendriksen/testing

Fix CSV download in UI, support excel formula reading + small stuff