Added aliasing support in Function Mocker

A small but important improvement for the trying to do-it-all testing tool.

I’ve updated function-mocker to add the missing support for aliased classes in both class and method declaration.
Trying to replace a class like this

use Acme\SomeClass;

class AnotherClass extends Class {
}

or one like this

use Acme\SomeClass as Alias;

class AnotherClass extends Alias {
}

or again one like this

use Acme\SomeClass as Alias;

class AnotherClass {

    function (Alias $param) {}
}

would have thrown exceptions around. Now no more.