add sc.lang.klass

## Class System in SCScript

All entries are objects that inherit from Object, like SuperCollider.
(ex: Integer class is an instance of Meta_Integer)

```javascript
1.class             // Integer
1.class.class       // Meta_Integer
1.class.class.class // Class

1.isKindOf(Object)            // true
Integer.isKindOf(Object)      // true
Meta_Integer.isKindOf(Object) // true
```

### Define a Class
register a new class.
```javascript
sc.lang.klass.define( className, superClassName, spec )
```

### Refine a Class
append instance/class methods to class in existing.
```javascript
sc.lang.klass.refine( className, spec )
```