Fixes trac issue #7473.

Removes encoder delay (skip samples) and writes remaining frame samples after EOF to get correct sample count.

Output is now accurate vs players that use Microsoft's codecs (Windows Media Format Runtime).

Tested vs encode>decode WMAv2 with MS's codecs and most sample rate/bit rate/channel/mode combinations in ASF/XWMA.
WMAv1 appears to use the same delay, from FFmpeg samples.
Signed-off-by: bnnm <bananaman255@gmail.com>