Correctly inherit parent methods, properties and constants

Parent methods, properties and constants override the elements of the
current class because the arrays were merged the wrong way around. This
commit fixes this by switching the order.
Implement support for Variadic arguments

Fixes https://github.com/phpDocumentor/phpDocumentor2/issues/629, in
this commit we add support for recognizing and displaying variadic
arguments as described in the Variadics RFC on Internals
(https://wiki.php.net/rfc/variadics).

This adds support for describing Variadics even before PHP 5.6, where
this feature is planned.
Merge branch 'master' of github.com:phpDocumentor/template.clean