Makes the underlying formatting process better handle native (non-string) types in a more flexible way. 2nd attempt since the last one got reverted due to breaking changes.
Closes https://github.com/jmbannon/ytdl-sub/issues/1394 Should help debug user issues like https://github.com/jmbannon/ytdl-sub/issues/1148 Checks permissions on the following: - working directory - output directory - cookiefile (if specified) And will fail immediately with a verbose message.