This allows the testing.ini to be set explicitly. Will you accept it?

Hi Ed,

I've added the ability to specify the testing.ini as an argument to the PyramidTestServer. This then allows you to specify which file is loaded explicitly. It will still default to testing.ini if none is given. This allows me to load configuration which isn't called testing.ini and from directories containing different test set ups.

All the best,

Oisin