Add more functions for convenience

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "Svelto.Common"]
-	path = Svelto.Common
-	url = https://github.com/sebas77/Svelto.Common.git

Svelto.ECS/EntitiesDB.cs

@@ -102,6 +102,26 @@ namespace Svelto.ECS.Internal
                 casted.ExecuteOnEntityView(entityGID.entityID, action);
         }
 
+        public void ExecuteOnEntity<T>(int id, ActionRef<T> action) where T : IEntityStruct
+        {
+            ExecuteOnEntity(new EGID(id, ExclusiveGroup.StandardEntitiesGroup), action);
+        }
+
+        public void ExecuteOnEntity<T>(int id, int groupid, ActionRef<T> action) where T : IEntityStruct
+        {
+            ExecuteOnEntity(new EGID(id, groupid), action);
+        }
+
+        public void ExecuteOnEntity<T, W>(int id, ref W value, ActionRef<T, W> action) where T : IEntityStruct
+        {
+            ExecuteOnEntity(new EGID(id, ExclusiveGroup.StandardEntitiesGroup), ref value, action);
+        }
+
+        public void ExecuteOnEntity<T, W>(int id, int groupid, ref W value, ActionRef<T, W> action) where T : IEntityStruct
+        {
+            ExecuteOnEntity(new EGID(id, groupid), ref value, action);
+        }
+
         public void ExecuteOnEntities<T>(int groupID, ActionRef<T> action) where T : IEntityStruct
         {
             int count;

Svelto.ECS/IEntitiesDB.cs

@@ -39,6 +39,12 @@ namespace Svelto.ECS
         void ExecuteOnEntity<T, W>(EGID egid, ref W value, ActionRef<T, W> action) where T : IEntityStruct;
         void ExecuteOnEntity<T>(EGID egid, ActionRef<T> action) where T : IEntityStruct;
         
+        void ExecuteOnEntity<T>(int id, ActionRef<T> action) where T : IEntityStruct;
+        void ExecuteOnEntity<T>(int id, int groupid, ActionRef<T> action) where T : IEntityStruct;
+        
+        void ExecuteOnEntity<T, W>(int id, ref W value, ActionRef<T, W> action) where T : IEntityStruct;
+        void ExecuteOnEntity<T, W>(int id, int groupid, ref W value, ActionRef<T, W> action) where T : IEntityStruct;
+        
         void ExecuteOnEntities<T>(int groupID, ActionRef<T> action) where T : IEntityStruct;
         void ExecuteOnEntities<T>(ActionRef<T> action) where T : IEntityStruct;