Changed the z-index for the modals, removed box-shadow from comment controls

sass/discussion/_modals.scss

@@ -10,6 +10,7 @@
   padding-bottom: 10px;
   position: absolute;
   text-align: center;
+  z-index: 1;
 
   h3 {
     background: $mit-red;

sass/discussion/_question-view.scss

@@ -181,6 +181,7 @@ div.question-header {
           aside.comment-controls {
             background: none;
             border: none;
+            @include box-shadow(none);
             display: inline-block;
             margin-top: -8px;
             padding:0 2% 0 0;