Update draft-ietf-httpbis-http2.xml

Adjust XSLT reference
Merge pull request #11 from michael-koeller/master

I adjusted the XSLT reference in the spec XML document
fix rfc2629.xslt reference
Consistently use "error code" instead of "status code" for stream and session related errors
Changed stream priority to be 31 bits long instead of 3 bits.
SETTINGS related changes as proposed in Tokyo

Added a note that settigs persistence might be removed in a future version.
Added a requrement on both sides to send SETTINGS as the first frame
after establishing an HTTP/2.0 connection.

Also added placeholder for the "magic" sequence before sending any frames.
Add issues backup target; initial backup
Update proposed clarification text in all documents.
Merge branch 'master' of github.com:http2/http2-spec
update issues
Merge pull request #32 from willchan/MaxNumConcurrentStreams

MaxNumConcurrentStreams: Update proposed clarification text in all documents. Fixes #19.
Major editorial cleanup for frame header changes.
Updating .html with changes.
Merging (with apparently no change).
Adding flow control warning.  Clarifying text around MAX_CONCURRENT_STREAMS.
Reformatting.
Updating flow control section for #16.
Removing CREDENTIAL frame (#39)
Clarifying stream creation and identification text (#30).
Updating references (#4).