-Events system update order is now choosen according to system priority

-added mixin for adding exluded components using it's type
-demos:
 *added GUI for selecting templates and choosing tools
 *change SpaceInvades SideMove system to not using events for better performance and multithreading
 *added Entites spawning support
 *fixed some Snake demo bugs
 *GUI work's better now

demos/source/gui/manager.d

@@ -7,18 +7,35 @@ import cimgui.cimgui;
 import ecs.std;
 import ecs.system;
 import ecs.vector;
+import ecs.entity;
 
 import gui.system;
+import gui.template_;
 
 extern(C):
 
 struct GUIManager
 {
     Vector!SystemGUI systems;
+    Vector!TemplateGUI templates;
 
+    uint selected_tempalte = 0;
+    
     void clear()
     {
+        foreach(tmpl; templates)
+        {
+            launcher.manager.freeTemplate(tmpl.tmpl);
+        }
+
         systems.clear();
+        templates.clear();
+    }
+
+    EntityTemplate* getSelectedTemplate()
+    {
+        if(templates.length > selected_tempalte)return templates[selected_tempalte].tmpl;
+        else return null;
     }
 
     void addSystem(ushort id, const (char)* name, bool enabled = true)
@@ -28,9 +45,19 @@ struct GUIManager
         systems.add(SystemGUI(name,system,enabled));
     }
 
+    void addTemplate(ushort[] components, const (char)* name)
+    {
+        templates.add(TemplateGUI(name, launcher.manager.allocateTemplate(components)));
+    }
+
+    void addTemplate(EntityTemplate* tmpl, const (char)* name)
+    {
+        templates.add(TemplateGUI(name, tmpl));
+    }
+
     void gui()
     {
-        if(igCollapsingHeader("Systems", ImGuiTreeNodeFlags_Framed))
+        if(igCollapsingHeader("Systems", ImGuiTreeNodeFlags_Framed | ImGuiTreeNodeFlags_SpanFullWidth | ImGuiTreeNodeFlags_FramePadding))
         {
             bool true_ = true;
             igIndent(8);
@@ -44,6 +71,27 @@ struct GUIManager
             }
             igUnindent(8);
         }
-        
+    }
+
+    void toolGui()
+    {
+        if(templates.length)
+        {
+            if(igBeginCombo("Template",templates[selected_tempalte].name,0))
+            {
+                foreach(i, tmpl; templates)
+                {
+                    if(igSelectable(tmpl.name,false,0,ImVec2(0,0)))
+                    {
+                        selected_tempalte = cast(uint)i;
+                    }
+                }
+                igEndCombo();
+            }
+        }
+        else 
+        {
+            if(igBeginCombo("Template",null,0))igEndCombo();
+        }
     }
 }

demos/source/gui/template_.d

@@ -0,0 +1,9 @@
+module gui.template_;
+
+import ecs.entity;
+
+struct TemplateGUI
+{
+    const (char)* name;
+    EntityTemplate* tmpl;
+}