[Hydra] improved checks for 1-D vector size
Merge pull request #400 from jgrewe/hydra_vector

Handle 1-d selection of n-data in Hydra for std::vector args
DataArray: add appendData method

This function implements the same logic as the append
method of the DataSet objec tin nixpy.
[test] add checks for DataArray::appendData
Merge pull request #404 from gicmo/appendData

Support appending of data to a DataArray
LGTM, thanks