enable tinymce lists plugin

fixes CNVS-29833

test plan:
- thoroughly regression test list behavior in tinymce
  - explore list functionality with the patchset
  - create complex nested lists before applying the patchset and make
    sure they display/edit/save okay with the patchset
  - explore using tab, backspace, and delete
  - explore using lists with text selection
  - explore using lists + indent/outdent
- specifically, make sure nested lists are html semantic

Change-Id: Iaf64f348644fc7c9edcacb36f2513bb6f78a3150
Reviewed-on: https://gerrit.instructure.com/84643
Reviewed-by: John Corrigan <jcorrigan@instructure.com>
Tested-by: Jenkins
QA-Review: Jeremy Putnam <jeremyp@instructure.com>
Product-Review: Simon Williams <simon@instructure.com>

app/coffeescripts/editor/stocktiny.coffee

@@ -10,6 +10,7 @@ define [
   'bower/tinymce/plugins/textcolor/plugin'
   'bower/tinymce/plugins/link/plugin'
   'bower/tinymce/plugins/directionality/plugin'
+  'bower/tinymce/plugins/lists/plugin'
 ], (markScriptsLoaded, punch) ->
 
   # prevent tiny from loading any CSS assets
@@ -25,6 +26,7 @@ define [
     "plugins/textcolor/plugin"
     "plugins/link/plugin"
     'plugins/directionality/plugin'
+    'plugins/lists/plugin'
   ]
 
   tinymce

public/javascripts/bower/tinymce/plugins/lists/plugin.js

@@ -11,6 +11,7 @@
 /*global tinymce:true */
 /*eslint consistent-this:0 */
 
+define(['bower/tinymce/tinymce'], function(tinymce){
 tinymce.PluginManager.add('lists', function(editor) {
 	var self = this;
 
@@ -811,3 +812,4 @@ tinymce.PluginManager.add('lists', function(editor) {
 		}
 	});
 });
+});

public/javascripts/tinymce.config.js

@@ -49,7 +49,7 @@ define([], function(){
       theme: "modern",
       skin: "light",
       skin_url: "/vendor/tinymce_themes/light",
-      plugins: "autolink,media,paste,table,textcolor,link,directionality",
+      plugins: "autolink,media,paste,table,textcolor,link,directionality,lists",
       external_plugins: {
         "instructure_image": "/javascripts/tinymce_plugins/instructure_image/plugin.js",
         "instructure_links": "/javascripts/tinymce_plugins/instructure_links/plugin.js",