Fix: Meta toString method

Useful for debugging purposes.

Author: emilforslund

src/main/java/com/speedment/codegen/base/Meta.java

@@ -88,5 +88,10 @@ public Impl<A, B> setRenderStack(RenderStack stack) {
             this.stack = stack;
             return this;
         }
+
+        @Override
+        public String toString() {
+            return "Impl{" + "model=" + model + ", result=" + result + ", transform=" + transform + ", factory=" + factory + ", stack=" + stack + '}';
+        }
     }
 }