Remove possibility of multiple spaces in the {content} tag

Hey,

I've been having issues with a site that places gallery shortcodes at the beginning of their posts.

This causes issues with excess whitespace being left after the strip_tags call, making the automatically generated broadcast message require manual editing a majority of the time.

This change fixes that (whilst maintaining linebreaks) and I don't believe will cause any issues with people who don't experience the issue.

Thoughts?

Adrian.