Improve mobile editing

assets/editor/main.html

@@ -5,12 +5,16 @@
 
 {{define "content"}}
 <script>
+    document.body.classList.add('edit-mode');
     if (sessionStorage.getItem('editor-wide') === '1') document.body.classList.add('editor-wide');
 </script>
 <form id="edit-form" class="edit-form" method="POST" action="{{.PostURL}}">
     {{if ge .SectionIndex 0}}<input type="hidden" name="section" value="{{.SectionIndex}}">{{end}}
     {{if ge .InsertBefore 0}}<input type="hidden" name="insert_before" value="{{.InsertBefore}}">{{end}}
     <div class="editor-toolbar">
+        <button type="button" class="btn btn-tool" data-action="undo" title="Undo">↶</button>
+        <button type="button" class="btn btn-tool" data-action="redo" title="Redo">↷</button>
+        <span class="toolbar-sep"></span>
         <button type="button" class="btn btn-tool" data-action="bold"      data-key="B" title="Bold (B)">**</button>
         <button type="button" class="btn btn-tool" data-action="italic"    data-key="I" title="Italic (I)">*</button>
         <span class="dropdown">
@@ -74,7 +78,7 @@
     <div id="editor" class="editor-cm"></div>
     <textarea name="content" id="editor-content" hidden>{{.RawContent}}</textarea>
 </form>
-<script src="/_/editor/vendor/codemirror.bundle.js"></script>
+<script src="/_/editor/vendor/codemirror.bundle.js?v={{editorBundleVersion}}"></script>
 <script src="/_/editor/tables.js"></script>
 <script src="/_/editor/dates.js"></script>
 <script src="/_/editor/movie.js"></script>