Fix pts conversions.

There aare two changes in this pull request:
1) pts is treated as microseconds. This fixes playback after 35 minutes.
2) I've looked how hibrys codec transfers frames to libhibris and implemented the same scheme. Now I don't wait untill MFC queue is full and return frames when they are ready. But I still maintain MFC queue full if possible. This partially fixes kludge for interlaced video.

There is still problem with 1080i kludge: sometimes MFC locks up and does not return any frames. So my kludge does not detect the problem. I'll fix it in separate commit.