Merge branch dassh_ci into development: addressing PyDASSH CI issues

During the course of CI implementation, it has been observed that PyDASSH tests occasionally fail due to an inability to locate output files. This MR aims to fix this issue.

One possible cause is that in the test(s) that have failed, the temporary file path was being identified in an ad hoc way. In the dassh_ci branch, the two affected tests in test_pydassh_run have been modified to use the user_object.workding_dir attribute for a direct reference.

@pshriwise - How will we know if this fixes the issue?