htparse: enhancements and bug fixes

CONNECT method supported. Fixed _str8cmp and _str9cmp comparison.
Support no content-length case.  Fixed hook_uri_run args. Run
hook_on_hdrs_complete if no header field is present. Supported empty
header value. Case insensitive match for particular header values
(e.g., keep-alive).

examples/htparse/htparse.h

@@ -32,6 +32,7 @@ enum htp_method {
     htp_method_LOCK,
     htp_method_UNLOCK,
     htp_method_TRACE,
+    htp_method_CONNECT,
     htp_method_UNKNOWN
 };