fix https://codereview.appspot.com/7092050/diff/5001/spdy/spdy_test.go#newcode616
udpte HeaderDictionary from string to []byte
HeaderDictionary to headerDictionary (not export)
update Copyright 2011 to 2013
update dictionary doc
update draft link from http2 to spdy/3
update package doc
update doc start with subject
HeaderValueSeparator to headerValueSeparator (not exported)
fix RSTStatusCode to RstStreamStatus
udpate RstStreamStatus difinission
add GoAwayStatus type
fix some docs
remove Frame Format document
remove todo for pending
remove unuseful comments
remove todo for do it later