Parse TiddlyWiki classic wikitext as plain text

Too many errors if we try to parse it as TW5 wikitext

core/modules/parsers/textparser.js

@@ -25,6 +25,7 @@ var TextParser = function(type,text,options) {
 
 exports["text/plain"] = TextParser;
 exports["text/html"] = TextParser;
+exports["application/vnd.tiddlywiki2"] = TextParser;
 exports["application/javascript"] = TextParser;
 exports["application/json"] = TextParser;