[lsdvd] Print cell range for chapters, and sector range for cells

In addition to showing the startcell, also show the lastcell.

Signed-off-by: Earl Chew <earl_chew@yahoo.com>
[lsdvd] Avoid loss of precision when computing durations

Use rational arithmetic when computing and summing video durations
to allow counting frame by frame. Only convert to real numbers when
computing displayed quantities.

Signed-off-by: Earl Chew <earl_chew@yahoo.com>
[lsdvd] Print exact durations in programmatic output

Include durations as rational numbers when generating programmatic
output so that computations can be exact.

Signed-off-by: Earl Chew <earl_chew@yahoo.com>