Module doesn't work well with PHP

Issue Summary

If you enable the TinyMCE module and you edit a node that has the 'PHP evaluator' filter then TinyMCE will just ignore this and strip out the PHP completely.

I seen that there was some commented code in 6.x-1.1-dev that was meant to work around this but it wasn't very good (it assumed that the format with the ID '2' was a PHP format).

I modified the commented code so that looks through the node's format and sees if any filters belong to the PHP module. I've attached the patch, hopefully you will find it useful.

Thanks!