Update stats-vbucket-seqno.md

The separating character was something strange, changed it to an ASCII colon.
Add protocol change proposals
Snapshot Marker: set Extra Length correctly
Snapshot Marker: Total body was wrong
Stream request: fix errors

This commit contains fixes according to the plans for the new
spec.
Updated snapshot-marker according to change 35198

Change 35198 [1] describes the new fields of the snapshot marker.

[1]: http://review.couchbase.org/35198
Flags are 4 bytes long

According to change 35922 [1] the flags field is 4 bytes long.

[1]: http://review.couchbase.org/35922
Merge pull request #12 from vmx/stream-request-no-highseq

Stream request: fix errors
Move updated stream request command into transport spec
Move updated snapshot marker command into transport spec
Rename index.md to README.me

Now the contents of the repository is nicely outlined when you look
at it on Github.
Fix typo in NOOP protocol message
Add flow control and connection notifier images
Fixing the body length in upr control message example