Change Collapsible km-icon class to specific arrow classes in CSS code

Author: Dimo Dimov

styles/mobile/common/collapsible.less

@@ -55,7 +55,8 @@
     overflow: hidden;
 }
 
-.km-icon-right .km-icon
+.km-icon-right .km-arrow-s,
+.km-icon-right .km-arrow-n
 {
     float: right;
 }
@@ -65,7 +66,8 @@
     clear: right;
 }
 
-.km-icon-top .km-icon
+.km-icon-top .km-arrow-s,
+.km-icon-top .km-arrow-n
 {
     display: block;
     margin: 0 auto;