Mock generator now handles variadic arguments in method

Here is the sample test I used:

```php
<?php

namespace
{
    class foo
    {
        public function bar(... $bar)
        {

        }

        public function baz(\stdClass... $bar)
        {

        }
    }
}

namespace tests\units
{
    use atoum;

    class foo extends atoum
    {
        public function testBar()
        {
            $this
                ->given($mocked = new \mock\foo)
            ;
        }
    }
}

```
Not sure that variadic is compatible with `&`.