in-memory bivalent vector-buffered streams with file-position and with-output-to-sequence (hope)fully works.

darcs-hash:42fe7deba65cb630649435249e364c9bbc0e43f1

Supported encodings: EBCDIC-US, ASCII, ISO-8859-1, UTF-8, UTF-16 and UTF-32.

darcs-hash:5cf32cbae0f59d58e2d84bcd31f0d92fae32441d