Various bug fixes and improvements

Added

• Add --cacert and --proxy-cacert options

Fixed

• Link_download_full: don't FREE(NULL)
• Correct error message in FREE()
• Error handling for fs_open and getopt_long
• Fix IO error with funkwhale subsonic API
• Fix --insecure-tls in help and README

What's Changed

• Fix --insecure-tls in help and README by @moschlar in #101
• Two small patches by @nwf-msr in #104
• Add --cacert and --proxy-cacert by @nwf-msr in #109
• Fix IO error with funkwhale subsonic API by @rdelaage in #106

New Contributors

• @moschlar made their first contribution in #101
• @nwf-msr made their first contribution in #104
• @rdelaage made their first contribution in #106

Full Changelog: 1.2.3...1.2.4