Populate HTTP warning codes

Includes changing 201 "Server Error" to "Internal Server Error"
List mostly borrowed from here http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
418 and 451 also added
Local testing showed a problem with 202 reported as "Server Error" instead of "Accepted"

mongoose.c

@@ -1544,23 +1544,72 @@ static void parse_http_headers(char **buf, struct mg_connection *ri) {
 
 static const char *status_code_to_str(int status_code) {
   switch (status_code) {
+  
+    case 100: return "Continue";
+    case 101: return "Switching Protocols";
+    case 102: return "Processing";
+      
     case 200: return "OK";
     case 201: return "Created";
+    case 202: return "Accepted";
+    case 203: return "Non-Authoritative Information";
     case 204: return "No Content";
+    case 205: return "Reset Content";
+    case 206: return "Partial Content";
+    case 207: return "Multi-Status";
+    case 208: return "Already Reported";
+    case 226: return "IM Used";
+      
+    case 300: return "Multiple Choices";
     case 301: return "Moved Permanently";
     case 302: return "Found";
+    case 303: return "See Other";
     case 304: return "Not Modified";
+    case 305: return "Use Proxy";
+    case 306: return "Switch Proxy";
+    case 307: return "Temporary Redirect";
+    case 308: return "Permanent Redirect";
+      
     case 400: return "Bad Request";
+    case 401: return "Unauthorized";
+    case 402: return "Payment Required";
     case 403: return "Forbidden";
     case 404: return "Not Found";
     case 405: return "Method Not Allowed";
+    case 406: return "Not Acceptable";
+    case 407: return "Proxy Authentication Required";
+    case 408: return "Request Timeout";
     case 409: return "Conflict";
+    case 410: return "Gone";
     case 411: return "Length Required";
-    case 413: return "Request Entity Too Large";
+    case 412: return "Precondition Failed";
+    case 413: return "Payload Too Large";
+    case 414: return "URI Too Long";
     case 415: return "Unsupported Media Type";
+    case 416: return "Requested Range Not Satisfiable";
+    case 417: return "Expectation Failed";
+    case 418: return "I\'m a teapot";
+    case 422: return "Unprocessable Entity";
     case 423: return "Locked";
-    case 500: return "Server Error";
+    case 424: return "Failed Dependency";
+    case 426: return "Upgrade Required";
+    case 428: return "Precondition Required";
+    case 429: return "Too Many Requests";
+    case 431: return "Request Header Fields Too Large";
+    case 451: return "Unavailable For Legal Reasons";
+      
+    case 500: return "Internal Server Error";
     case 501: return "Not Implemented";
+    case 502: return "Bad Gateway";
+    case 503: return "Service Unavailable";
+    case 504: return "Gateway Timeout";
+    case 505: return "HTTP Version Not Supported";
+    case 506: return "Variant Also Negotiates";
+    case 507: return "Insufficient Storage";
+    case 508: return "Loop Detected";
+    case 510: return "Not Extended";
+    case 511: return "Network Authentication Required";
+      
     default:  return "Server Error";
   }
 }