consider adding setOutput() to write renderers to a stream instead of a file path

_Original author: b...@processing.org (June 07, 2010 01:20:07)_

This bug automatically added from:
http://dev.processing.org/bugs/show_bug.cgi?id=1502

Comment from fry, 2010-03-11 05:34

already added to PGraphicsPDF for 0179, but might be useful for other
renderers. this is a follow-on from bug #1343.

_Original issue: http://code.google.com/p/processing/issues/detail?id=246_
