[DSOUND] add DirectSoundFullDuplex support

[Molle Bestefich]

Molle Bestefich wrote:
> Pros:
>  - Developers of patches will not get pissed (ahem) for their stuff
> not getting in.
>  - Development doesn't stop just every time a release is coming up.
>  - Developers can actively select whether they'd like to help with the
> release (switch to '0.9-rc' branch) or do a little more crazy stuff
> (switch to trunk).
>  - Only sane patches get accepted to the RC by picking and merging
> those that are approved some way or another.
>  - Patches don't get "LOST" as you call it..
>
> Cons:
>  - Can't think of any?

Ok, maybe there's one.  You need a release manager to pick which
patches gets in the RC / release.

But there must be a million ways of doing that automatically, besides
from having an actual release manager.  Script your way out of it. 
Automatically merge patches with 'bugfix' or 'Release-Ok' in commit
text.  Automatically merge patches < 100 lines long.  Hohum. 
Whatever.  I can think of more, I'm sure you can too.