Added phpdoc_seperation fixer

Replaces #845.
It makes a massive difference!

**Example if we run them the wrong order:**

Before:
```php
    /**
     * @param string $foo
     * @return bool
     */
```

after:
```php
    /**
     * @param  string $foo
     *
     * @return bool
     */
```

Note how the param is now not aligned correctly.