fix sequencer bug

make EnginesRoot dispose itself

Svelto.ECS/EnginesRoot.Engines.cs

@@ -12,7 +12,7 @@ using Svelto.ECS.Profiler;
 
 namespace Svelto.ECS
 {
-    public partial class EnginesRoot : IDisposable
+    public partial class EnginesRoot
     {
 #if ENGINE_PROFILER_ENABLED && UNITY_EDITOR        
         static EnginesRoot()

Svelto.ECS/EnginesRoot.Entities.cs

@@ -11,7 +11,7 @@ using Svelto.ECS.Profiler;
 
 namespace Svelto.ECS
 {
-    public partial class EnginesRoot : IDisposable
+    public partial class EnginesRoot: IDisposable
     {
         /// <summary>
         /// Dispose an EngineRoot once not used anymore, so that all the
@@ -26,6 +26,13 @@ namespace Svelto.ECS
             
             foreach (var engine in _disposableEngines)
                 engine.Dispose();
+            
+            GC.SuppressFinalize(this);
+        }
+
+        ~EnginesRoot()
+        {
+            Dispose();
         }
 
         ///--------------------------------------------

Svelto.ECS/EnginesRoot.Submission.cs

@@ -14,7 +14,7 @@ using Svelto.ECS.Profiler;
 
 namespace Svelto.ECS
 {
-    public partial class EnginesRoot : IDisposable
+    public partial class EnginesRoot
     {
         void SubmitEntityViews()
         {

Svelto.ECS/Sequencer.cs

@@ -104,7 +104,7 @@ namespace Svelto.ECS
             _steps = steps;
         }
 
-        public void Next<C>(IEngine engine, C condition, EGID id) where C:struct,IConvertible
+        public void Next<C>(IEngine engine, C condition, EGID id) where C:struct, IConvertible
         {
             C branch = condition;
             var to = (_steps._steps[engine] as To<C>);
@@ -120,7 +120,7 @@ namespace Svelto.ECS
             var to  = _steps._steps[engine];
             var steps = to.engines;
             
-            if (steps != null)
+            if (steps != null && steps.Length > 1)
                 for (var i = 0; i < steps.Length; i++)
                     steps[i].Step(id);
             else