Clarify no duplicate instances of HTTP2-Settings

I think this is strictly an editorial clarification, not a technical
change.
Merge pull request #178 from MikeBishop/master

Clarify no duplicate instances of HTTP2-Settings
chmod -x
Merge branch 'master' of github.com:http2/http2-spec
Backing up issues.
Adding text about potential flow control deadlock.  Closes #185.
Fixing flow control example. Closes #182.
Adding restriction on PUSH_PROMISE usage.  Closes #175.  Fixes #177.
Clarifying illegal uses of RST_STREAM.  Fixes #176.
Refactoring of priority text for #175.  Adding note about use of PRIORITY for frame transmission prioritization vs. processing prioritization.
Capturing the conclusion of duplicate settings discussion in Berlin.  Closes #174.
Noting magic string exception for version identification rules.  Fixes #173.
Clarifying the use of frames of different types in the reserved states.  Closes #165.
Ensuring the method is shown in uppercase.
Reorganizing in preparation for #172.
Making some contributions toward TLS1.1/1.2 text (#172).
Documented the stream number 1 semantics.

Also clarified that stream close cancels reservations made by PUSH_PROMISE.
Added TLS Server Name Indication reference

Also some minor TLS text cleanup
fix typo
header field reg: make spec link more precise