Fixes, fail testing:

Core:

* Test buffer_cat iterator move members

HTTP:

* Fixed yield / resume in writer
* Fixed message serialization with chunked encoding

* Test yield / resume in writer
* Test all conditional branches during message serialization
* Test chunked encoding
* Increase coverage on parse_error
* Add parse_error::general

WebSocket:

* Add error::general
* Increase coverage in error

include/beast/http/parse_error.hpp

@@ -34,7 +34,9 @@ enum class parse_error
 
     invalid_chunk_size,
 
-    short_read
+    short_read,
+
+    general
 };
 
 class parse_error_category : public boost::system::error_category
@@ -97,7 +99,7 @@ public:
             return "unexpected end of data";
 
         default:
-            return "beast::http::parser error";
+            return "parse error";
         }
     }