Fix outstanding build issues and parser audit results
* Give SBuf I/O buffer directly to Http1::RequestParser
* Redesign parser state engine to represent the current state
being parsed instead of previous completed. This allows much
more incremental resume of a parse and reliable consume() of
the input buffer as sections complete instead of complex byte
accounting outide the parser.
* Maintain an internal counter of bytes parsed and consumed by
the parser instead of a buffer offset. This allows much more
reliable positioning of the state/section boundaries.
* Remove erroneous fprintf debug left in previous commit.
* Redesign HttpRequestMethod constructor to drop end parameter.
* Redesign all parser unit tests. Marking RFC non-compliance
for future fixing.