fixed exec of custom nodes with duplicate inputs
test for exec custom node with duplicate inputs
language test placeholder for duplicate func params
better language test
verify warnings in the language test
Merge pull request #2862 from Steell/custom-node-duplicate-input

Fixed evaluation of custom nodes with duplicate input names: MAGN-4436, MAGN-4885
Merge commit '4cc2008be568226f3a476' into Revit2015