Use big colorful pills for switch between MR tabs

app/assets/stylesheets/sections/merge_requests.scss

@@ -20,18 +20,14 @@
 }
 
 .merge-request .merge-request-tabs{
-  border-color: #AAA;
+  border-bottom: 2px solid $border_primary;
+  padding-bottom: 10px;
+  margin-bottom: 20px;
+
   li {
     a {
-      border-color: #AAA;
-      padding: 14px 40px;
+      padding: 20px 40px;
       font-size: 14px;
-      background-color: #F9F9F9;
-    }
-    &.active a {
-      border-color: #AAA;
-      border-bottom-color: #FFF;
-      background-color: #FFF;
     }
   }
 }

app/views/projects/merge_requests/_show.html.haml

@@ -7,7 +7,7 @@
   = render "projects/merge_requests/show/participants"
 
   - if @commits.present?
-    %ul.nav.nav-tabs.merge-request-tabs
+    %ul.nav.nav-pills.merge-request-tabs
       %li.notes-tab{data: {action: 'notes'}}
         = link_to project_merge_request_path(@project, @merge_request) do
           %i.icon-comment