mov: Add option to keep exact packet sequence after seeking

The current behavior may produce a different sequence of packets
after seeking, compared to demuxing linearly from the beginning.
This is because the MOV demuxer seeks in each stream individually,
based on timestamp, which may set each stream at a slightly different
position than if the file would have been read sequentially.

This makes implementing certain operations, such as segmenting,
quite hard, and slower than need be.

Therefore, add an option which retains the same packet sequence
after seeking, as when a file is demuxed linearly.
