Remove fa-fw class from all icons

Often it is desirable to NOT have this class applied, and it is easier
to apply its styles if needed rather than un-apply it.

less/lib/Select.less

@@ -16,4 +16,5 @@
   margin-left: -30px;
   pointer-events: none;
   color: @control-color;
+  .fa-fw();
 }