Decode HTML entities before passing to htmLawed

Some websites encode the title or content of their feeds with HTML
entities (for example the Wired feed). HtmLawed doesn't recognize
tags that are already entity encoded, so we have to decode them first
in order for htmLawed to neutralize/remove all tags correctly.
Merge pull request #293 from seanrand/fix-entities-html-tags

Decode HTML entities before passing title or content to htmLawed