Incorrect number of trials for RVG16_B01

[jthermiz]

There are only 118 trials list for /clusterfs/NSDS_data/nwb/test/RVG16/RVG16_B01.nwb but there should be 120 (60 for stimulus and 60 for baseline).

[JesseLivezey]

Another stim parsing problem for a tone150 block:

ValueError: ToneTokenizer: Incorrect number of stimulus onsets found in block RVG06_B06. Expected 4500, found 4496.

[jihyunbak]

We were missing the first mark in wn2 blocks - this can be fixed if a lower threshold was used (0.1 instead of 0.3), as implemented in PR #130. We had the same observation before (for example #102), but we understand a little better now: the first mark is smaller than all the other markers in the recorded mark time series.

This is probably because the mark for wn2 starts right at the beginning of the audio file (although not sure exactly why)...