adding transfection_method as well as dependency to require transfection_type if you have a transfection_method per ticket #1798
finishing merge
Merge remote-tracking branch 'origin/master' into 1798-transfection-method
merging master onto 1798 branch
reversed logic for dependency
Merge pull request #430 from ENCODE-DCC/1798-transfection-method

1798 transfection method