Add audio buffer option to audio config

[oviano]

Description

This adds an option to set the audio buffer, rather than be forced to use 10ms.

Motivation and Context

I am trialing the library in a personal hobby project and I found that with a 10ms buffer, I was getting audio glitches so I needed to raise it. 80ms is apparently recommended by MSDN, and 50ms is the default used inside FFmpeg.

How Has This Been Tested?

Testing with my project shows the audio is more stable when I increase the buffer.

Types of changes

Tweak (non-breaking change to improve existing functionality)

Checklist:

My code has been run through clang-format.
I have read the contributing document.
My code is not on the master branch.
The code has been tested.
All commit messages are properly formatted and commits squashed where appropriate.
I have included updates to all appropriate documentation.

[Fenrirthviti]

Please properly fill out the PR template instead of deleting it.

[Lain-B]

For clarification, you say "more stable." Does that mean it's still unstable? What device are you observing this issue with? It would be good to have more information on the actual issue itself you're experiencing (unless you already filed an issue, in which case please make sure to link it).

[Lain-B]

Oh geez this PR is really old, I'm really sorry it took so long to respond to this. I think this just flew over our heads a bit last year and we didn't put it on our task list for whatever reason at the time.

[oviano]

It’s ok, I long since stopped using the library anyway so feel free to close this if you like.

[Lain-B]

I know you're not using libdshowcapture anymore but this needs a minor API version before we merge. Otherwise it's fine though.

[RytoEX]

I know you're not using libdshowcapture anymore but this needs a minor API version before we merge. Otherwise it's fine though.

@Lain-B If we need to bump this before we merge, I can do that.