fixed firefox outline bugs

common/lib/xmodule/xmodule/css/sequence/display.scss

@@ -73,6 +73,11 @@ nav.sequence-nav {
         padding: 0;
         position: relative;
         @include transition();
+        outline: 0;
+
+        &:focus {
+          outline: 0;
+        }
 
         &:hover {
           background-color: #fff;
@@ -211,7 +216,7 @@ nav.sequence-nav {
   ul {
     position: absolute;
     top: 0;
-    list-style: none;
+    list-style: none !important;
     height: 100%;
     right: 0;
     top: 0;
@@ -238,6 +243,11 @@ nav.sequence-nav {
           width: 40px;
           text-indent: -9999px;
           @include transition(all, .2s, $ease-in-out-quad);
+          outline: 0;
+
+          &:focus {
+            outline: 0;
+          }
 
           &:hover {
             opacity: .5;

common/lib/xmodule/xmodule/css/video/display.scss

@@ -101,6 +101,11 @@ div.video {
             @include transition(background-color, opacity);
             width: 14px;
             background: url('../images/vcr.png') 15px 15px no-repeat;
+            outline: 0;
+
+            &:focus {
+              outline: 0;
+            }
 
             &:empty {
               height: 46px;
@@ -171,6 +176,11 @@ div.video {
             @include transition();
             -webkit-font-smoothing: antialiased;
             width: 116px;
+            outline: 0;
+
+            &:focus {
+              outline: 0;
+            }
 
             h3 {
               color: #999;