Comment 2 for bug 841378

This patch fixes that. If the file length is the same for both the file of the clip that is getting replaced and the new file, it uses the same in and out points.
It also fixes two other minor issues:
1) If a folder was right clicked, a separator was shown at the bottom of the menu.
2) If something that wasn't a video clip was right clicked on the timeline, double separators were shown in the menu.