Restore previous version of CAudioPlayer fields.

Restore previous version of CAudioPlayer fields.

Addressed code review comments:
Move channel mute, channel solo, and channel count from IMuteSolo to CAudioPlayer.
Deferred support for IMuteSolo to CMIDIPlayer deferred until we hear back from working group.
Move comment marker to correct location.

We discussed the code review comments and agreed to restore the
previous handling of channel mute, channel solo, and channel count.
We will probably have to review this again later, depending on what
the working group says about MIDI Player. To make it easier to
examine the history later, I'm submitting the previous change as
is, followed immediately by this change which addresses the code
review comments.

Change-Id: I4d5594d70c1c2d5fb90980a8a0414177ff29d4a7