catch SampleSheetError in openDirDialog validateSampleSheet()->getCsvReader() raises SampleSheetError if file contains null bytes / non-csv file.
catch SampleSheetError in openDirDialog
validateSampleSheet()->getCsvReader() raises SampleSheetError if file contains null bytes / non-csv file.

phac-nml/irida-miseq-uploader,phac-nml/irida-miseq-uploader