[Frontend] Styling for tree item when its being edited

open #278
Work in progress

platform/commonUI/themes/snow/res/sass/_constants.scss

@@ -156,6 +156,7 @@ $colorItemTreeVCHover: $colorKey;
 $colorItemTreeFg: $colorBodyFg;
 $colorItemTreeSelectedBg: pushBack($colorKey, 15%);
 $colorItemTreeSelectedFg: $colorBodyBg;
+$colorItemTreeEditingBg: #b2624a;
 $colorItemTreeVC: $colorBodyFg;
 $colorItemTreeSelectedVC: $colorBodyBg;
 $shdwItemTreeIcon: none;