Rename Sequence to Segments #277
Description
to match vocalpy: vocalpy/vocalpy#127
This would obviously be breaking change but I think it's important to do this, to convey that these annotation formats are the result of segmentation, and to reserve the word "sequence" to mean "a sequence of sounds produced by an animal" -- a sequence is by definition made up of segments, but not all segments are part of a sequence
We could also change the actual implementation when we do so -- I need to revisit + reread the code in detail but when I skim now I get the feeling it could be simplified, e.g. we could represent a set of line segments with a dataframe and then switch the implementation of properties like onsets_s to just return the column as values instead of the setter/getter pattern we use now.