i.e. trasform XYZ bytes to something readable

Allow `colorN' and `colourN' (where 0 <= N < 256) as color specifier.

`attr' now follows the same rule as `fg' and `bg', with the three airity variant. Attributes by themselves are a comma-separated list of keywords, each one representing a ncurses attribute.

currently unused, will help later when adding colour support

prevent telescope from dying when connecting to non-tls/non-gemini servers (found by trying to load a bogus ``gemini://gemini.nytpu.com'' -- the correct url for the capsule is ``gemini://nytpu.com'')