Bidirectional text improvements (#4541)

* Add support for \dir pragma

* Add "dir" attribute to reveal, edit, edit-text and edit-codemirror widgets

* Add  $:/config/DefaultTextDirection hidden setting

* Revert accidentally commited test data

This reverts some of commit b83c1d160f.

* Remove Codemirror plugin from Prerelease

Makes it easier to test things

* Fix framed text editor directionality in Firefox

* Add direction attribute for edit body template

* Missed closing brace

* Add docs for \dir pragma

* Templates should set text direction from a variable, not a transclusion

* Updates to framed.js in the light of PRs that have been merged since this

* Restore whitespace trim

* Docs dates

* Fix typo

* Clarify docs

core/modules/parsers/wikiparser/rules/dir.js

@@ -0,0 +1,51 @@
+/*\
+title: $:/core/modules/parsers/wikiparser/rules/dir.js
+type: application/javascript
+module-type: wikirule
+
+Wiki pragma rule for specifying text direction
+
+```
+\dir rtl
+\dir ltr
+\dir auto
+```
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+exports.name = "dir";
+exports.types = {pragma: true};
+
+/*
+Instantiate parse rule
+*/
+exports.init = function(parser) {
+	this.parser = parser;
+	// Regexp to match
+	this.matchRegExp = /^\\dir[^\S\n]*(\S+)\r?\n/mg;
+};
+
+/*
+Parse the most recent match
+*/
+exports.parse = function() {
+	var self = this;
+	// Move past the pragma invocation
+	this.parser.pos = this.matchRegExp.lastIndex;
+	// Parse tree nodes to return
+	return [{
+		type: "element",
+		tag: this.parser.parseAsInline ? "span" : "div",
+		attributes: {
+			dir: {type: "string", value: this.match[1]}
+		},
+		children: []
+	}];
+};
+
+})();

core/modules/parsers/wikiparser/wikiparser.js

@@ -36,6 +36,7 @@ options: see below:
 */
 var WikiParser = function(type,text,options) {
 	this.wiki = options.wiki;
+	this.parseAsInline = options.parseAsInline;
 	var self = this;
 	// Check for an externally linked tiddler
 	if($tw.browser && (text || "") === "" && options._canonical_uri) {