Catch error when a slide has no content
Catch error when a slide has no content

.split() gives us an empty array when there's no content, so we can't
call .trim() on a null. Instead, return an empty string and just make
sure we trim the title before we pass it on.

binford2k/showoff,puppetlabs/showoff,puppetlabs/showoff,marrero984/showoff,binford2k/showoff,slambert/showoff,slambert/showoff,marrero984/showoff,puppetlabs/showoff,binford2k/showoff,marrero984/showoff,binford2k/showoff,marrero984/showoff,slambert/showoff,puppetlabs/showoff,slambert/showoff