PHP 5.4.30 5.5.14 5.6.0-rc* compat

This patch allows instantiation of internal classes even though they don't allow custom un-serialization.

Hereby, we simply extend those classes and override their constructors.

TODOs:

 - [x] check security implications
 - [x] check for other internal classes with this problem
 - [x] check for `final` in either the class or the constructor of the class?
 - [x] check whether a class is an abstract type?
 - [x] provide exceptions for un-solvable cases