add play youku implemention

Signed-off-by: Jack <jack.wgm@gmail.com>
add libyk to vc2005 project

Signed-off-by: Jack <jack.wgm@gmail.com>
add buffing for class avplayer

Signed-off-by: Jack <jack.wgm@gmail.com>
add buffing for class avplayer_impl

Signed-off-by: Jack <jack.wgm@gmail.com>
revert main.cpp

Signed-off-by: Jack <jack.wgm@gmail.com>
Merge branch 'master' of https://github.com/Jackarain/avplayer
Merge pull request #6 from Jackarain/master

add buffering interface