Fix typo: s/does is/is/
Merge pull request #97 from willchan/TypoFix

Fix typo: s/does is/is/
Updates from pmcmanus review.
Switching to ALPN.  Closes #59.
Clarifying flow control requirements.  Closes #87.
Removing references to browsers and user-agents. Closes #27.  Removing DoS considerations in favor of #93 (or similar).
Giving due credit, belatedly.