Make sure that searching for the empty string returns all available tiddlers

Makes sense because every tiddler contains the empty string. This
restores the functionality of the tag editor dropdown.

core/modules/wiki.js

@@ -878,7 +878,7 @@ exports.search = function(text,options) {
 	// Function to check a given tiddler for the search term
 	var searchTiddler = function(title) {
 		if(!searchTermsRegExps) {
-			return false;
+			return true;
 		}
 		var tiddler = self.getTiddler(title);
 		if(!tiddler) {