Added a failing spec for the ArrayContainMatcher with non string values

While reviewing the code of PhpSpec today, I figured that the ArrayContainMatcher does not work properly for non-scalar values (when there is a failure): it will try to cast the value as string as it uses ``$presenter->presentString()``:

```
$ ./bin/phpspec run spec/PhpSpec/Matcher/ArrayContainMatcherSpec.php --no-ansi

      PhpSpec\Matcher\ArrayContainMatcher

  21  Ô£ö is a matcher
  26  Ô£ö responds to contain
  31  Ô£ö matches array with specified value
  36  Ô£ÿ does not match array without specified value
        expected exception of class "PhpSpec\Exception\Example"..., but got
        [exc:PhpSpec\Exception\Example\ErrorException("notice: Object of class stdClass could not be converted to int in
        C:\wamp\www\phpspec\src\PhpSpec\Matcher\ArrayContainMatcher.php line 28")].
  42  Ô£ö matches array without specified value

----  failed examples

        PhpSpec\Matcher\ArrayContainMatcher
  36  Ô£ÿ does not match array without specified value
        expected exception of class "PhpSpec\Exception\Example"..., but got
        [exc:PhpSpec\Exception\Example\ErrorException("notice: Object of class stdClass could not be converted to int in
        C:\wamp\www\phpspec\src\PhpSpec\Matcher\ArrayContainMatcher.php line 28")].


5 examples (4 passed, 1 failed)
73ms

```

As I wanted to play a bit with PhpSpec, I implemented the failing spec instead of just reporting the issue.

there is 2 ways to fix it:

- quick bug fix, keeping the logic as is but restricting ``supports`` to scalar arguments
- changing the way the exception message is build to support any value in the array.

I obviously think the second solution is better for functionalities but I don't know the code enough yet to figure the best way to do it. Would it simply be switching to ``presentValue`` ?