fixed null text error

lms/static/coffee/src/customwmd.coffee

@@ -45,6 +45,7 @@ $ ->
 
     removeMath: (text) ->
 
+      text = text || ""
       @math = []
       start = end = last = null
       braces = 0

lms/static/coffee/src/discussion/views/thread_response_view.coffee

@@ -11,7 +11,6 @@ class @ThreadResponseView extends DiscussionContentView
   render: ->
     @$el.html(@template(@model.toJSON()))
     @initLocal()
-    console.log @$local
     @delegateEvents()
     if window.user.voted(@model)
       @$(".vote-btn").addClass("is-cast")