Add peer and staff grading required display, notifications

lms/static/coffee/src/staff_grading/staff_grading.coffee

@@ -318,7 +318,7 @@ class StaffGrading
 
   problem_link:(problem) ->
     link = $('<a>').attr('href', "javascript:void(0)").append(
-      "#{problem.problem_name} (#{problem.num_graded} graded, #{problem.num_pending} pending)")
+      "#{problem.problem_name} (#{problem.num_graded} graded, #{problem.num_pending} pending, required to grade #{problem.num_required} more)")
         .click =>
           @get_next_submission problem.location
 

lms/templates/peer_grading/peer_grading.html

@@ -29,7 +29,7 @@
                 <ul class="problem-list">
                 %for problem in problem_list:
                     <li>
-                    <a href="${ajax_url}problem?location=${problem['location']}">${problem['problem_name']} (${problem['num_graded']} graded, ${problem['num_pending']} pending)</a>
+                    <a href="${ajax_url}problem?location=${problem['location']}">${problem['problem_name']} (${problem['num_graded']} graded, ${problem['num_pending']} pending, required to grade ${problem['num_required']} more)</a>
                     </li>
                 %endfor
                 </ul>