## Link to GitHub Issue or related Pull Request, if one exists
#730
## Description of change
Add an option that extracts channels from 7.1 ASIO and presents to 2-ch
ASIO. Same idea as the SDVX 2ch fix except for gitadora we are
duplicating the center channel to front.
## Testing
Tested SDVX and GFDM Arena.
## Link to GitHub Issue or related Pull Request, if one exists
n/a
## Description of change
Create `WrappedAsio`, similar to how we wrap `IAudioEndpoint`
So far, the wrapper does these things:
1. logging (for diagnosis, since iidx and gfdm don't produce any logs
when asio succeeds)
2. iidx32+ hack to work around refcount mismatch issue
3. sdvx valk cab hack to force 2-channel audio ("downmixing" by taking
only the front channels)
4. honor volume boost
As a result of `#2` the mempatch was removed from `iidx.cpp` since we
can tackle it cleanly in the hook. `#3` also removes the need for manual
patches.
Real downmixing is hard & expensive on the CPU so it was not
implemented.
## Testing
Tested iidx/sdvx/gfdm with xonar and flexasio
bicarusandGitHub