moreover used this slots when downloading a gemini stream
This changes means that the parsing of gemini stream is no more done
in program events but during the downloading thread.
See, for example the changes in: 'gemini-viewer:make-gemini-download-event'
- added a parameter to prevent notification when downloading a gemini stream
see 'gemini-viewer:request-stream-gemini-document-thread';
- added a more human friendly constants for each gemini status code
(e.g. +success+ for code 20).
- as the gemini parser has status added a parameter ('initialize-parser') to
'gemini-parser:parse-gemini-file' (default to nil, do not initialize);
- initialize the gemini parser when needed.
the implementation more or less follow
gemini://mozz.us/files/rfc_gemini_favicon.gmi but it does render the
first character of the file instead of checking for emoji
characters.