Merge pull request #26 from Chris00/master

Allow <summary type="html">
Try to always decode HTML <content> and <summary>

Some feed have

    <summary type="html"><![CDATA[ ... ]]></summary>
    <content type="html"><![CDATA[ ... ]]></content>
    <content type="html"> (escaped HTML) </content>

This commit tries to decode the HTML into a structured representation.