Transliterate servername to safe ASCII

Fixes #3410

core/modules/server/server.js

@@ -30,7 +30,7 @@ function Server(options) {
 	this.routes = options.routes || [];
 	this.authenticators = options.authenticators || [];
 	this.wiki = options.wiki;
-	this.servername = this.wiki.getTiddlerText("$:/SiteTitle") || "TiddlyWiki5";
+	this.servername = $tw.utils.transliterateToSafeASCII(this.wiki.getTiddlerText("$:/SiteTitle") || "TiddlyWiki5");
 	// Initialise the variables
 	this.variables = $tw.utils.extend({},this.defaultVariables);
 	if(options.variables) {

core/modules/utils/transliterate.js

@@ -916,4 +916,10 @@ exports.transliterate = function(str) {
 	});
 };
 
+exports.transliterateToSafeASCII = function(str) {
+	return str.replace(/[^\x00-\x7F]/g,function(ch) {
+		return exports.transliterationPairs[ch] || ""
+	});
+};
+
 })();