SpacingTop feature added

Author: vovayatsyuk

lib/web/mage/sticky.js

@@ -11,7 +11,8 @@ define([
 
     $.widget('mage.sticky', {
         options: {
-            container: ''
+            container: '',
+            spacingTop: 0
         },
 
         /**
@@ -42,6 +43,12 @@ define([
             if( !isStatic && this.element.is(':visible') ) {
                 offset = $(document).scrollTop() - this.parentOffset;
 
+                if (typeof this.options.spacingTop === 'function') {
+                    offset += this.options.spacingTop();
+                } else {
+                    offset += this.options.spacingTop;
+                }
+
                 offset = Math.max( 0, Math.min( offset, this.maxOffset) );
 
                 this.element.css( 'top', offset );