Portaudio DLLs (release) for Windows

* Used PortAudio v19 from http://www.portaudio.com/download.html
* Used cmake to create project files for VS2012 (32bit and 64bit)
* No DirectX backend support yet [if required, I need to set up directx
first]
* Added preprocessor macro PA_WDMKS_NO_KSGUID_LIB to fix build
(http://code.google.com/p/dolphin-emu/issues/detail?id=5662)
Merge pull request #4 from holyhead/master

Portaudio DLLs (release build) for Windows