casm import fails unless an import settings file is provided

[deober]

Found during an import of casm_0.3 data to casm_1.X.

Using "casm import --batch batchfile.txt" fails to import any energy data from the old casm project.

Using an import settings file with "casm import --batch batchfile.txt -s import_settings.json" works properly.

[bpuchala]

Thank you for the report, I'll address this.