Use tile avatars for user/group show pages

app/assets/stylesheets/generic/avatar.scss

@@ -15,6 +15,10 @@
     &.s24 { margin-right: 4px; }
   }
 
+  &.avatar-tile {
+    @include border-radius(0px);
+  }
+
   &.s16 { width: 16px; height: 16px; margin-right: 6px; }
   &.s24 { width: 24px; height: 24px; margin-right: 8px; }
   &.s26 { width: 26px; height: 26px; margin-right: 8px; }

app/views/groups/show.html.haml

 .dashboard
   %div
-    = image_tag group_icon(@group.path), class: "avatar s90"
+    = image_tag group_icon(@group.path), class: "avatar avatar-tile s90"
     .clearfix
       %h2
         = @group.name

app/views/users/show.html.haml

 .row
   .col-md-8
     %h3.page-title
-      = image_tag avatar_icon(@user.email, 90), class: "avatar s90", alt: ''
+      = image_tag avatar_icon(@user.email, 90), class: "avatar avatar-tile s90", alt: ''
       = @user.name
       - if @user == current_user
         .pull-right