Mostly bugfix update + empty components support and remove EntityID from Event structure

-empty components now take no memory, so flag components is now far better
-added test for critical bug
-fixed critical bug with adding/removing entities form inside events
-fixed small bug with TestRunner
-improve basic tests
-fixed betterC compilation on DMD
-remove EntityID form Event structure
-added "return" attribute to some functions
-moved some code from Tempalte side to actual implementation
-fixed bug with EntityTemplate copying
-commented out some possibliy unused code
-use code formatter

tests/bugs.d

@@ -0,0 +1,142 @@
+module tests.bugs;
+
+import tests.basic;
+
+import bubel.ecs.core;
+import bubel.ecs.manager;
+import bubel.ecs.system;
+import bubel.ecs.attributes;
+
+version(GNU)
+{
+	pragma(inline, true) T[n] staticArray(T, size_t n)(auto ref T[n] a)
+	{
+		return a;
+	}
+}
+else import std.array : staticArray;
+
+@("Bug0001")
+unittest
+{
+    struct Event1
+    {
+        mixin ECS.Event;
+
+        EntityID id;
+    }
+
+    struct Event2
+    {
+        mixin ECS.Event;
+    }
+
+    struct System1
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            CInt[] int_;
+        }
+
+        EntityTemplate* tmpl;
+        EntityID id;
+
+        void onCreate()
+        {
+            tmpl = gEM.allocateTemplate([CInt.component_id, CLong.component_id].staticArray);
+        }
+
+        void onDestroy()
+        {
+            gEM.freeTemplate(tmpl);
+        }
+
+        void handleEvent(Entity* entity, Event1 event)
+        {
+            gEM.removeEntity(event.id);
+            gEM.sendEvent(entity.id,Event2());
+        }
+
+        void handleEvent(Entity* entity, Event2 event)
+        {
+            id = gEM.addEntity(tmpl,[CInt(2).ref_, CLong(8).ref_].staticArray).id;
+        }
+    }
+
+    struct System2
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            Entity[] entity;
+        }
+
+        ///check if every entity was removed correctly
+        void onUpdate(EntitiesData data)
+        {
+            assert(0);
+        }
+    }
+
+    struct System3
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            uint length;
+            Entity[] entity;
+        }
+
+        ///remove every entity
+        void onUpdate(EntitiesData data)
+        {
+            foreach(i;0..data.length)gEM.removeEntity(data.entity[i].id);
+        }
+    }
+
+    gEM.initialize(0);
+
+    gEM.beginRegister();
+
+    gEM.registerComponent!CInt;
+    gEM.registerComponent!CFloat;
+    gEM.registerComponent!CDouble;
+    gEM.registerComponent!CLong;
+    gEM.registerComponent!CShort;
+    gEM.registerComponent!CFlag;
+
+    gEM.registerEvent!Event1;
+    gEM.registerEvent!Event2;
+
+    gEM.registerSystem!System1(0);
+    gEM.registerSystem!System2(-200);
+    gEM.registerSystem!System3(-200);
+
+    gEM.endRegister();
+
+    EntityTemplate* tmpl = gEM.allocateTemplate([CInt.component_id, CLong.component_id].staticArray);
+    EntityID id = gEM.addEntity(tmpl,[CLong(10).ref_, CInt(6).ref_].staticArray).id;
+    EntityID id2 = gEM.addEntity(tmpl,[CInt(4).ref_].staticArray).id;
+    gEM.freeTemplate(tmpl);
+    gEM.commit();
+
+    gEM.sendEvent(id2, Event1(id));
+
+    gEM.getSystem(System2.system_id).disable();
+
+    gEM.begin();
+    gEM.update();
+    gEM.end();
+
+    gEM.getSystem(System2.system_id).enable();
+
+    gEM.begin();
+    gEM.update();
+    gEM.end();
+
+    gEM.destroy();
+}