Added display of tracked formant frequencies
Changed the bounds of formant calculation

Extended the right boundary of vowel formant calculation from the end of
the vowel (in ASR phone alignment results) to the end of the trailing
phoneme).

The rationale is that in the ASR phone alignment results, the onset of the
trailing stop consonant often creeps into the vowel a little bit.
Thus ending the formant tracking right at the end of the ASR-aligned vowel
would lead to loss of critical information.
Improved the display of formant results
Improved the group-level formant results.

Added a new way of calculating group-level formant compensation results:
calculating the pert-noPert difference first, and then perform the
between-subjects averaging. This is probably better than the old method,
because it affords a more straightforward way of getting the SEM measure.

Added display of group-level (between-subject) SEM.