Upgrade to TinyMCE 4.5.1

- New flat theme (with padding tightened a bit from the default to fit
  in right-hand pane)
- Adds search/replace within notes
- Adds URL autolinking
- Image pasting/dragging is now properly disallowed (though TinyMCE 4
  has hooks that may allow us to actually support this by automatically
  creating attachments)
- New blockquote style with color bar
- Replaces custom context menu on link click with built-in version

 To-do:

- Fix display of pop-ups, which are now modal dialogs within the note
  frame instead of pop-up windows, to stay fully within the frame
- Localize (more important now that there are tooltips)
- Support image dragging
- Update elements list for HTML5, for better drag-and-drop?
- Move directionality control to context menu instead of taking up
  toolbar space?
- Evaluate other plugins for potential inclusion
- Show additional controls in separate note window?
- Fix opacity of text in tooltips

Closes #451, closes #421

resource/tinymce/plugins/directionality/plugin.js

@@ -0,0 +1,64 @@
+/**
+ * plugin.js
+ *
+ * Released under LGPL License.
+ * Copyright (c) 1999-2015 Ephox Corp. All rights reserved
+ *
+ * License: http://www.tinymce.com/license
+ * Contributing: http://www.tinymce.com/contributing
+ */
+
+/*global tinymce:true */
+
+tinymce.PluginManager.add('directionality', function(editor) {
+	function setDir(dir) {
+		var dom = editor.dom, curDir, blocks = editor.selection.getSelectedBlocks();
+
+		if (blocks.length) {
+			curDir = dom.getAttrib(blocks[0], "dir");
+
+			tinymce.each(blocks, function(block) {
+				// Add dir to block if the parent block doesn't already have that dir
+				if (!dom.getParent(block.parentNode, "*[dir='" + dir + "']", dom.getRoot())) {
+					if (curDir != dir) {
+						dom.setAttrib(block, "dir", dir);
+					} else {
+						dom.setAttrib(block, "dir", null);
+					}
+				}
+			});
+
+			editor.nodeChanged();
+		}
+	}
+
+	function generateSelector(dir) {
+		var selector = [];
+
+		tinymce.each('h1 h2 h3 h4 h5 h6 div p'.split(' '), function(name) {
+			selector.push(name + '[dir=' + dir + ']');
+		});
+
+		return selector.join(',');
+	}
+
+	editor.addCommand('mceDirectionLTR', function() {
+		setDir("ltr");
+	});
+
+	editor.addCommand('mceDirectionRTL', function() {
+		setDir("rtl");
+	});
+
+	editor.addButton('ltr', {
+		title: 'Left to right',
+		cmd: 'mceDirectionLTR',
+		stateSelector: generateSelector('ltr')
+	});
+
+	editor.addButton('rtl', {
+		title: 'Right to left',
+		cmd: 'mceDirectionRTL',
+		stateSelector: generateSelector('rtl')
+	});
+});