modified ObjectWalker to handle private properties in parent classes

[lgsgbr]

ObjectWalker can handle private properties in parent classes with this modification. Tested. Please merge it into master.

[rdohms]

@lgsgbr does this have any side effects, other then it will start reading parent properties it used to not read?

I think it would be better to put this under a configuration flag, with the default not including parent properties to not break current usage and easily allow people to start using it with the flag.

[lgsgbr]

@rdohms , no, it doesn't have any side effects. But I think, this is not a special case. Here is an example:

class A
{
    /**
     * @Filter\Trim
     */
    private $field;

    public function getField()
    {
       return $this->field;
    }
}

class B extends A
{
    /**
     * @Filter\Trim
     */
    private $anotherField;

    public function getAnotherField()
    {
        return $this->anotherField;
    }
}

$filter->filter(new A()); // it's OK
$filter->filter(new B()); // throws Exception

Without modificating the loader this example throws exception on class B because of a limitation in ReflectionClass::getProperties() method. Because of this I think it would be better to handle private properties in parent classes by default.
If you still prefer a configurable behavior, I can modify the solution. Shall I make it?

[rdohms]

@lgsgbr yes, if you could do that it would be great, less breakage and in the future we can then deprecate it.

Thank you very much!