Added patch to implement exclusive mode in PulseAudio backend

Hi,

This patch implements exclusive mode for winepulse, which is, as far as I can tell, the one major thing it's missing that winealsa has.

Because it's quite hard to get hold of a program which uses exclusive mode in order to test this, I've uploaded a quick and dirty hack of one of the PortAudio examples: http://burntcomma.com/pulse-exclusive.tar.gz. Choose one of the WASAPI input devices and say Y for exclusive mode; it'll record for a few seconds and then play it back.

Thanks