-move code from templates to ECS side:

*sendEvent - using EventRef (alias to ComponentRef)
 *ListenerCallData now contain entities count and pointer to EntityInfo
 *Remove system_pointer from SystemCallData (use context instead)
 *Register event
-Now all BECS functinality can be used without templates
-clean code

tests/basic.d

@@ -648,6 +648,8 @@ unittest
 
         void onAddEntity(EntitiesData data)
         {
+            foreach(i; 0..data.length)
+               data.long_[i] += 1;
             add++;
             assert(add_order == 1);  
             add_order++;