Jdmtool

- Unbreak Python versions 3.7, 3.8, 3.9, 3.10

- Fix refreshing services: the server started requiring the `cov_check` parameter
- Download sff files and keychain (though not used yet)
- Add a helper script for inspecting chartview files

- Fix a crash when downloading files without crc32
- Improve UI

- First release
- Supports programming GNS 430W