intensity cutoff occurs before start of AY segment

[scjs]

I have an AY vowel token that causes getTimeOfF1Maximum() to raise a ValueError, because trimmedFormants returns an empty list.

I think this is happening because the maximum intensity is very early in the intensity curve, and the intensity drops off right away, so getIntensityCutoff() chooses a cutoff that only spans the first few intensity frames. This is an issue because the timestamps for those intensity frames are used to trim the formant frames, and the formant frames may start later than the intensity frames (there's no formant measurements at the very edges). In my token, the first formant frame is 7ms after the first intensity frame, so if the intensity cutoff occurs before the 7th 1ms intensity frame, no formant frames will be returned by trimFormants().

One way to fix this which might address #22 also, would be to take measurements in a way that intensity and formant frames are synced up. Or, a smaller fix could be made in faav(), modifyIntensityCutoff(), or getTimeOfF1Maximum() to make sure that the end_cutoff time is not before the first formant frame.