libhb: Sanitize BD chapter durations
It appears some BDs have invalid chapter durations, see
https://forum.handbrake.fr/viewtopic.php?f=12&t=30479

This compares chapter start time deltas and title duration to chapter
duration to make best guess corrections.

Note that chapter events generated by libbluray are based on the chapter
start times. So the start time should be trusted more than the duration.


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6292 b64f7644-9d1e-0410-96f1-a4d463321fa5