Changes to videoClip logic and faceDetector attributes

Changed videoClip logic to calculate frame durations, it's now giving me
112 frame detections (the whole clip), instead of 83 detections. The
calculation relies on the frame count (hardcoded) so any other clip
would break it.

Also changed relativeFaceSize attribute of faceDetector to give me more
than 60% successful detections in the videoClip. The duration of a
detection went up by a factor of about 2 (twice as slow but twice as
accurate). More testing needed to figure out the best configuration.