[WIP] [ZF3] Refactor input filter component

Hi everyone,

This is a branch I'm working on on my free time, to refactor the input filter component for ZF 3. I mostly push this for people who want to see the code and help.

It is not yet usable because it relies on some refactoring I'm doing in both Validator and Filter components. It completely embraces the service manager, so now we should not have the VERY annoying problem of adding custom validators/filters, and not being able to use them using the short name because it uses plugin managers that were not fetched from SM.

Under the hood, the component is completely rewritten and now uses SPL RecursiveFilter. From my first experiments, this allow an around x5-8 performance improvements and a memory consumption divided by 13 for complex input filters.

What I've seen is that the input filter component got more and more bloated, and it is now slow as hell. Checking the isValid method as it is now makes it quite clear where the problem is.

Therefore, for ZF3, I suggest that the base input filter to stay as simple as possible, and people wanting to have custom behaviors to extend the class and override the isValid for their use-cases (as a more general rule, I'd like this for most components too).

To help this, it also uses internally SPL RecursiveFilter. Basically, it allows to have very powerful validation group rules. For instance, this branch features a ValidationGroupRegex filter, and usage would be as follow:

```php
$inputFilter = new InputFilter();
// … populate the input filter with lot of fields

// You can use the as-usual validation group:
$inputFilter->setValidationGroup(array('username', 'email'));

// But also some more complex rules. Here it only validate fields that contain 'registration-'
// in their names
$validationGroupRegex = new ValidationGroupRegexFilter($inputFilter, '/registration-/i')
$inputFilter->setValidationGroupFilter($validationGroupRegex);
```

What do you think ? :)