Pass test instance to closure in exception asserter and when handler

This allows users on PHP 5.3 to do:

```php
<?php

use atoum;

class myTest extends atoum
{
	public function testFoo()
	{
		$this
			->given($this->newTestedInstance)
			->then
				->exception(function($test) {
					$test->testedInstance->throwingException();
				})
					->isInstanceOf('runtimeException')
					->hasMessage('Random exception message')
		;
	}
}
```

Bye bye `use`!
Pass test instance to closure in output asserter
CS fix
Merge pull request #353 from jubianchi/closure-asserter-test-instance

Pass test instance to closure asserters