Fixed docstring for cancelAllJobs. Patch from Sylvain GARANCHER.
Added bindings for CUPS streaming API.

This patch adds a binding for cupsCreateJob(), cupsStartDocument(),
cupsWriteRequestData(), and cupsFinishDocument(), and declares the
CUPS_FORMAT_* constants (used for "startDocument" arguments).

Patch from Sylvain GARANCHER.
Updated NEWS.