Restructure joyent message parser (from Node.js):

* New http::raw_parser wrapper
* Convert parser errors to error_code
* Enumeration and strings for parsed HTTP method
* Move parser engine into joyent namespace
* Rename includes to be distinct

beast/http/HTTP.cpp

@@ -21,4 +21,5 @@
 
 #include "impl/URL.cpp"
 #include "impl/ParsedURL.cpp"
-#include "impl/http_parser.cpp"
+#include "impl/joyent_parser.cpp"
+#include "impl/raw_parser.cpp"