Perform correct, strict parsing of the request line, handling the

Perform correct, strict parsing of the request line, handling the
http protocol tag, url and method appropriately, and attempting
to extract values even in the presence of unusual whitespace in
keeping with section 3.5, prior to responding with whatever
error reply is needed. Conforms to RFC7230 in all respects,
the section 3.5 optional behavior can be disabled by the user
with a new HttpProtocolOptions StrictWhitespace flag. In all
cases, the_request is regenerated from the parsed components
with exactly two space characters.

Shift sf's 'strict' method check from the Strict behavior because
it violates forward proxy logic, adding a new RegisteredMethods
flag, as it will certainly be useful to some.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1756729 13f79535-47bb-0310-9956-ffa450edef68