Define Minimum Event Length in Seconds

[Breakthrough]

Right now min scene length is set to 2 frames, which may be undesirable at higher framerates. Most test footage is between 10 and 60 frames per second, so say 0.05 seconds is a good lower bound. Even that seems like a quite small number of frames for most common use cases, so doubling that to 0.1 seconds seems like a better default.