improve class names

Svelto.ECS/EnginesRoot.Engines.cs

@@ -61,10 +61,10 @@ namespace Svelto.ECS
             else            
                 _otherEngines.Add(engine);
             
-            var queryableEntityViewEngine = engine as IQueryingEntityViewEngine;
+            var queryableEntityViewEngine = engine as IQueryingEntitiesEngine;
             if (queryableEntityViewEngine != null)
             {
-                queryableEntityViewEngine.EntityDb = _DB;
+                queryableEntityViewEngine.entitiesDB = _DB;
                 queryableEntityViewEngine.Ready();
             }
         }

Svelto.ECS/IQueryingEntitiesEngine.cs

@@ -0,0 +1,9 @@
+namespace Svelto.ECS
+{
+    public interface IQueryingEntitiesEngine : IEngine
+    {
+        IEntityDB entitiesDB { set; }
+
+        void Ready();
+    }
+}

Svelto.ECS/IQueryingEntityViewEngine.cs

@@ -1,9 +0,0 @@
-namespace Svelto.ECS
-{
-    public interface IQueryingEntityViewEngine : IEngine
-    {
-        IEntityDB EntityDb { set; }
-
-        void Ready();
-    }
-}