Hilight unread threads and forums (addresses #22)

I'm not sure this covers everything the initial submitter wanted, but it
goes a long way.
remove debug prints (oops)
Merge pull request #33 from eve-val/feature/unread-indicators

Hilight unread threads and forums (addresses #22)
Merge pull request #35 from eve-val/feature/spoiler-tags

Implement spoiler tags (fixes #31)
Invert the polarity on spoilers +/- button

I am a chump.