Cheat sheet updated for header and explanation. Video removed.

cms/templates/widgets/problem-edit.html

@@ -30,6 +30,17 @@
     <article class="simple-editor-cheatsheet">
         <div class="cheatsheet-wrapper">
             <div class="row">
+                <h6>Header</h6>
+                <div class="col sample">
+                    <img src="/static/img/header-example.png" />
+                </div>
+                <div class="col">
+<pre><code>H1
+=====
+</pre>
+                </div>
+            </div>
+            <div class="row">
                 <h6>Multiple Choice</h6>
                 <div class="col sample">
                     <img src="/static/img/choice-example.png" />
@@ -78,6 +89,18 @@
                     <pre><code>[[wrong, (right)]]</code></pre>
                 </div>
             </div>
+            <div class="row">
+                <h6>Explanation</h6>
+                <div class="col sample">
+                    <img src="/static/img/explanation-example.png" />
+                </div>
+                <div class="col">
+<pre><code>[explanation]
+A short explanation of the answer.
+[explanation]
+</code></pre>
+                </div>
+            </div>
         </div>
     </article>
 </script>

common/lib/xmodule/xmodule/js/spec/problem/edit_spec.coffee

@@ -257,8 +257,6 @@ describe 'MarkdownEditingDescriptor', ->
         [(] distractor
         [] no space
         
-        {{video abcd1s}}
-        
         Option with multiple correct ones
         [[one option, (correct one), (should not be correct)]]
         
@@ -312,8 +310,6 @@ describe 'MarkdownEditingDescriptor', ->
           </choicegroup>
         </multiplechoiceresponse>
         
-        <video youtube="1.0:abcd1s" />
-        
         <p>Option with multiple correct ones</p>
         
         <optionresponse>

common/lib/xmodule/xmodule/js/src/problem/edit.coffee

@@ -165,7 +165,7 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
     else
       return template
 
-# We may wish to add insertHeader and insertVideo. Here is Tom's code.
+# We may wish to add insertHeader. Here is Tom's code.
 # function makeHeader() {
 #  var selection = simpleEditor.getSelection();
 #  var revisedSelection = selection + '\n';
@@ -175,11 +175,6 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
 #  simpleEditor.replaceSelection(revisedSelection);
 #}
 #
-#function makeVideo() {
-#var selection = simpleEditor.getSelection();
-#simpleEditor.replaceSelection('{{video ' + selection + '}}');
-#}
-#
   @markdownToXml: (markdown)->
     toXml = `function(markdown) {
       var xml = markdown;
@@ -222,9 +217,6 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
         return groupString;
       });
 
-      // replace videos
-      xml = xml.replace(/\{\{video\s(.*?)\}\}/g, '<video youtube="1.0:$1" />\n\n');
-
       // replace string and numerical
       xml = xml.replace(/^\=\s*(.*?$)/gm, function(match, p) {
         var string;