Adds unit tests for Issue #118 and Multi-PersonName data elements
Adds unit tests for Issue #118 and Multi-PersonName data elements

These tests ensure that we can properly write decoded datasets and multivalue PersonNames.

NOTE: These were placed in test_filewriter.py for now since they directly test filewriter.py but they may be better suited for another test file.

carlomt/dicom_tools,carlomt/dicom_tools