Add line numbers and wrapping to xml, json, and html editors

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

@@ -2,6 +2,8 @@ class @HTMLEditingDescriptor
   constructor: (@element) ->
     @edit_box = CodeMirror.fromTextArea($(".edit-box", @element)[0], {
       mode: "text/html"
+      lineNumbers: true
+      lineWrapping: true
     })
 
   save: ->

common/lib/xmodule/xmodule/js/src/raw/edit/json.coffee

@@ -2,6 +2,8 @@ class @JSONEditingDescriptor extends XModule.Descriptor
   constructor: (@element) ->
     @edit_box = CodeMirror.fromTextArea($(".edit-box", @element)[0], {
       mode: { name: "javascript", json: true }
+      lineNumbers: true
+      lineWrapping: true
     })
 
   save: ->

common/lib/xmodule/xmodule/js/src/raw/edit/xml.coffee

@@ -2,6 +2,8 @@ class @XMLEditingDescriptor extends XModule.Descriptor
   constructor: (@element) ->
     @edit_box = CodeMirror.fromTextArea($(".edit-box", @element)[0], {
       mode: "xml"
+      lineNumbers: true
+      lineWrapping: true
     })
 
   save: ->