DestroyVoiceSafeEXT - Expose whether or not a voice was actually destroyed

About
-----
XAudio's function for exporting voices has the ability to fail - however, the
function declaration does not have a return value, so there is no way to safely
determine on the client side whether or not a voice was actually destroyed.
This extension adds a function that is otherwise identical, but includes a
result code to allow checking for failures.

Dependencies
------------
This extension does not interact with any non-standard XAudio features.

New Procedures and Functions
----------------------------
FAUDIOAPI uint32_t FAudioVoice_DestroyVoiceSafeEXT(FAudioVoice *voice);

How to Use
----------
This extension acts identially to the existing DestroyVoice, but with and added
return value - it will return 0 on success or non-0 on failure.
