* [ATOM_EXT,DOC] Improved example on replacing chars in an atom.
* [DCG_ASCII,NEW] Added ascii_letter//2, ascii_letter_uppercase//2, ascii_letter_lowercase//2 to allow for easy lower<->upper case conversion.
* [IANA_TO_RDF,SC] Vastly simplified codebase; not working yet (HTTP does not allow the stream to be repositioned).