Grammar refactoring

* Grammar refactoring WIP

* ISerializer.grammar

* Fixing various bugs in the grammar

* Small touch that improoves performance

* Fix unknown values grammar

* Various fixes

* Serialization refactoring to drop suboject logic

* Details fixed

* Entity attributes initialization refactoring

* JSDoc error fixed

* Rename value key to default

* Remove useless default

* Revert string keys

js/entity/NaturalNumberEntity.js

@@ -3,7 +3,7 @@ import Utility from "../Utility.js"
 
 export default class NaturalNumberEntity extends IntegerEntity {
 
-    constructor(values) {
+    constructor(values = 0) {
         super(values)
         this.value = Math.round(Utility.clamp(this.value, 0))
     }