force utf8 encoding if devforceupdate is on
parser: try to convert non-unicode feeds with specified encoding to utf8
before trying to remove dangling utf8 characters in case of utf8-related
libxml errors because doing so produces garbage content

parser: add charset recoding hack for systems where libxml is build without support for iconv (handles libxml error 32)

If the feed cannot be parsed there is not particular error but always "Unknown/unsupported feed type". The patch uses the error from the XML parser which gives more detailed error reporting.