Comment 22 for bug 722285

This patch works around the short comings of the underlying library. It dynamically scales the available range in the scrollbar to whatever OpenShot needs to control the timeline. If you set the zoom control to one second, you will still be able to scroll through all of a very long project (tested with a project of 3 hours length.) This scaling comes at the cost of making the scroll itself coarser the larger the project is. For the 3 hour long project I tested, moving the timeline thumb by one pixel moves the timeline itself by nearly 2 seconds.