Feeds can contain characters that are not valid XML
|Reported by:||westi||Owned by:|
It is possible for any of the feeds to contain control characters which are not valid in XML e.g. http://www.fileformat.info/info/unicode/char/1c/index.htm
When outputting user supplied content in an XML context we should strip these control characters - they are unprintable and just break feed parsers.
http://en.wikipedia.org/wiki/Valid_characters_in_XML has a good list of what is and isn't valid.
I guess we need a strip_for_xml() function or something.