Fix maximum recursion depth exceeded

- Fix the "maximum recursion depth exceeded" error by operating on the store object 'raw_name' instead of the store object names with hashes removed. For more details, see: https://github.com/craigmbooth/nix-visualize/issues/4. - Support output in CSV format to allow post-processing the results with other tools. CSV output simply exports node properties "raw_name" and "level". - Document the '--output' argument usage to allow result export in other formats also (e.g. svg, pdf, jpg). - Bump the version to 1.0.5.