Decouple I18n\View\Helper\AbstractTranslatorHelper from ext\intl

https://github.com/zendframework/zf2/blob/release-2.2.0rc1/library/Zend/I18n/View/Helper/AbstractTranslatorHelper.php#L34-L45

is too wide and involves also

https://github.com/zendframework/zf2/blob/release-2.2.0rc1/library/Zend/Form/View/Helper/AbstractHelper.php#L13

which has nothing to do with `ext\intl` apart for `FormMonthSelect` and its descendants

Without this fix, no `Form\View\Helper` can be used if `ext\intl` is missing.

I had to put some attribute initialization into constructors to avoid unmanagable fatal errors.