Split grammar (#15)

* Move grammar parsers to entity classes

* Fix includes

* Fix Entity5 test

* Small detail

* Fix unknown keys entities

* Persistent grammar objects

* Fix grammar

* Grammar from variable

js/entity/FunctionReferenceEntity.js

@@ -1,3 +1,4 @@
+import Grammar from "../serialization/Grammar.js"
 import GuidEntity from "./GuidEntity.js"
 import IEntity from "./IEntity.js"
 import ObjectReferenceEntity from "./ObjectReferenceEntity.js"
@@ -16,10 +17,14 @@ export default class FunctionReferenceEntity extends IEntity {
             type: GuidEntity,
         },
     }
-
     static {
         this.cleanupAttributes(this.attributes)
     }
+    static grammar = this.createGrammar()
+
+    static createGrammar() {
+        return Grammar.createEntityGrammar(this)
+    }
 
     constructor(values) {
         super(values)