Windows phone support

Hi,

I have prepared simple implementation of Windows Phone PUSH notifications.

For now it supports only Toast notifications, but that was needed for in my project and I won't add support for other options in near future, but maybe my code will help someone.
this config is wrong. Because of the way the Configuration class looks like, this will always be set (it will be ``true`` or ``false``). Your code means that it is impossible to disable the windowsphone support