Run: enable threading only when required for the protocol (>= HTTP/1.1)

When threaded, the server is more likely to crash from socket send/recv/select issues, for reasons that are currently unclear. However, HTTP/1.0 seems to respond fast enough from a single thread, so threading isn't strictly needed there.

src/snake/Run.hx

@@ -79,7 +79,12 @@ class Run {
 		RunHTTPRequestHandler.cacheEnabled = cacheEnabled;
 		RunHTTPRequestHandler.silent = silent;
 		var httpServer = new RunHTTPServer(new Host(address), port, RunHTTPRequestHandler, true, directory);
-		httpServer.threading = true;
+		// HTTP/1.1 basically requires threads due to keeping the connection
+		// open after response, so we have no choice but to enable threading.
+		// ideally, it would be threaded for HTTP/1.0 too, but for reasons that
+		// are currently unclear, socket errors are causing crashes when
+		// threaded. better to prefer stability until it can be resolved.
+		httpServer.threading = protocol >= "HTTP/1.1";
 
 		if (openBrowser) {
 			var url = 'http://${address}:${port}';