Implement `new` static method for `SimpleObject`

Due to architecture of PHP for calling method on the newly create object, you need to wrap it into brackets.

```php
$obj = (new MyObjectClass)->something()->orChained();
```

This construction is extremely uncomfortable to use, for this purpose `new` static method should be introduced:
```php
$obj = MyObjectClass::new()->something()->orChained();
```
