Fix live streams that produce zero timestamp

Streams stop playing with client buffer (NetStream.bufferTime) greater than zero (0) in Flash Media Server live streams.

Restart live stream playback at least once every three weeks to ensure the timestamps move forward.

When streaming for an extended period (greater than 24 days), server timestamps stop moving forward properly. This event can cause issue for live streaming with a player buffer where the stream enters a buffering state that does not terminate.