Remove trailing whitespace
Clean up proof of Lemma 5
Minor cleanup of lemmas 6 and 7
Fix url in contact info
Fix scale term in lemma 7 UI claim

I've been scaling by (\sum c)^2 which is bigger than necessary and
completely screws up the resulting arguments. The correct term is
(\sum c^2); and now that's what's written down.
Minor cosmetic change: remove blank line and obsolete eqn reference.