ffplay: increase AV_SYNC_THRESHOLD_MIN to 0.04

Less than 0.04 sec delays should not be noticable, and it helps us with 50fps
content where some timing errors can cause a frame dup where it is not really
necessary.

Signed-off-by: Marton Balint <cus@passwd.hu>
ffplay: fix compilation with Visual Studio

A patch by achristensen from trac.ffmpeg.org.

Fixes ticket #3580.

Signed-off-by: Marton Balint <cus@passwd.hu>
ffplay: try multiple sample rates if audio open fails

Should fix ticket #3509.

Signed-off-by: Marton Balint <cus@passwd.hu>
ffplay: fix typo in docs

Signed-off-by: Marton Balint <cus@passwd.hu>
ffplay: add support for toggling between multiple video filters with the w key

Signed-off-by: Marton Balint <cus@passwd.hu>