mibe/FeedWriter — pull request #23 by trepmag (2014-09-17 17:59:22+00:00)
Title: Replace invalid xml utf-8 chars in tag contents.

I was getting issue to validate some feeds and finally found that not all utf-8 chars are valid for xml: http://www.phpwact.org/php/i18n/charsets#xml

So this commit insert the function found in the above link and use it when a string must be inserted into content tags.