[dev] Text_diff changes for PHP5

[Michael Rubinsky]

Quoting Žilvinas Bartkus <zilvinas.bartkus at gmail.com>:

> Dear Michael,
>
> I saw you did last
> commit<http://git.horde.org/co.php/framework/Text_Diff/Diff.php?rt=horde&ws=1&r=1.29>for
> Text_Diff.
>
>    - It still contained errors for assigning results of new as a reference,
>    which was erroring on PHP5. Fix that.
>    - Also there was as usage of *is_a* function on renderer which was
>    deprecated. Upgraded so that it checks PHP version before using that
>    function.
>
>
> I attach fixed files. It would be great if you'd commit to CVS repository