vaapi: fix wrong frame size. blurry line at bottom. issue 328
example: fix command line encoding (win)

see qApp.arguments()
virtual dtors
StalledMedia status if demuxer is interrupt
speed up seeking
update 'capi' to fix qt4 build
fix avcodec properties not applied.

since AVDecoder::setOptions() add QMap support, FFmpeg decoder options
may be not merged into "avcodec" options.
Seems that we can apply some properties after AVCodecContext is open.
apply ffmpeg options on context if not null
frame extractor is faster using framedrop. faster preview.
apply skip frame options for all avcodec based decoders
vda: VideoFormat to CV pixel format. lion check
only drops frames not referenced by others to get complete images
environment var to disable ffmpeg log
interrupt timeout property for AVPlayer
video decoder doc. remove deprecated ff members

use setOptions() to set ffmpeg members
Merge pull request #2 from wang-bin/master

merge from upstream