added callable typehint support for PHP 5.4+
skipped PHP 5.3 incompatible test
Merge pull request #21 from bauer01/callable-typehint

callable typehint support for PHP 5.4+
Workaround for mocking some(!) internal classes [#18]

see http://forum.nette.org/cs/14953-mock-tridy-dedici-od-reflectionclass