improved play and stop button (#2692)

* improved play and stop button if only one record is allowed
* stop button first in action menu
* fix skin colors
* autofocus term field in search form
* fix responsive column layout in invoice listing
* improve responsive header for small screens

assets/sass/variables.scss

@@ -25,7 +25,7 @@ $green: #00a65a;
 // Info
 //$aqua: #00c0ef;
 // Warning
-//$yellow: #f39c12;
+$yellow: #f0ad4e;
 $blue: #0073b7;
 //$navy: #001F3F;
 //$teal: #39CCCC;