Have Student login/signup modals automatically focus first inputs

app/views/courses/StudentLogInModal.coffee

@@ -35,4 +35,8 @@ module.exports = class StudentSignInModal extends ModalView
 
   onClickCreateNewAccountLink: ->
     @trigger 'want-to-create-account'
-    @hide?()
+    @hide?()
+
+  afterInsert: ->
+    super()
+    _.delay (=> @$('input:visible:first').focus()), 500

app/views/courses/StudentSignUpModal.coffee

@@ -20,6 +20,10 @@ module.exports = class StudentSignUpModal extends ModalView
     @willPlay = options.willPlay
     @classCode = utils.getQueryVariable('_cc') or ''
 
+  afterInsert: ->
+    super()
+    _.delay (=> @$('input:visible:first').focus()), 500
+      
   onClickSkipLink: ->
     @trigger 'click-skip-link' # defer to view that opened this modal
     @hide?()