Video loader crashes when reading past end of file

[spillerrec]

Describe the bug The video loader loads X frames from a file, but if this means the last frame is after the end of the video, it will still try to load those frames and crash due to them not being available.

[spillerrec]

It did not crash due to being unable to read the frames, it threw an exception upon reaching the end and the importer dialog did not handle this, causing the crash. It now catches the exception so the crash is avoided, but it would be nice with a bit smoother handling.