No need to compare value two times
Pre compute hash and index for often used header names
Optimize DefaultHttpHeaders.contains(...)
Not lookup Content-Length multiple times
Revert "Pre compute hash and index for often used header names"

This reverts commit 113861186ca8a0cfb6559f8dba42347c55c44f31.
Improve DefaultHttpHeaders lookup performance
Share some code
Valide header name while calculate the index
No need to validate known header names and values
Skip validation of header when adding during decode
Minimize access to ThreadLocal
Rewrite HttpObjectDecoder to use ByteToMessageDecoder
Only parse initial line one time
WIPF
Rewrite HttpObjectDecoder to make use of a proper state machine and so speed up perf
Fix limit the header size
No need to create a new String array for each parsed initial line
Correctly handle whitespaces and trailing whitespaces while parse headers
Bug fixes in the HttpObjectDecoder and test cases
Cleanup