Fix small bug when subgroups start overlap without subgroupStack (#2527)

* Fix redraw order

* Fix error when option is not defined

* Allow template labels

* Fix boolean types bug

* Add subgroup stacking

* Almost finish subgroup stacking

* Play with examples for subgroup order

* Fix stacked subgroups

* Fix subgroup stacking

* Add stackSubgroups option

* Fix example

* Add docs

* Fix onRemove item subgroups recalculate

* Return subgroup example and add stackSubgroup example

* Split stackSubgroup example to subgroup/html and expectedVsActualTimesItems.html

* Fix small bug when subgroups start overlap

lib/timeline/Stack.js

@@ -177,7 +177,7 @@ exports.collision = function(a, b, margin, rtl) {
  */
 exports.collisionByTimes = function(a, b) {
   return (
-    (a.start < b.start && a.end > b.start && a.top < (b.top + b.height) && (a.top + a.height) > b.top ) ||
-    (b.start < a.start && b.end > a.start && b.top < (a.top + a.height) && (b.top + b.height) > a.top )
+    (a.start <= b.start && a.end >= b.start && a.top < (b.top + b.height) && (a.top + a.height) > b.top ) ||
+    (b.start <= a.start && b.end >= a.start && b.top < (a.top + a.height) && (b.top + b.height) > a.top )
   )
 }