Improved error checking: automatically list and/or find track options.

[jonathancrabtree]

In the case where this happens:

WARN - option 'color' at line 12 is not supported by glyphs of type 'rectangle' and has been ignored WARN - option 'feat-tag-name' at line 12 is not supported by glyphs of type 'rectangle' and has been ignored WARN - option 'label-feat-function' at line 13 is not supported by glyphs of type 'label' and has been ignored

circleator could either list all of the available options for the given feature type, and/or make a suggestion at which one was intended by looking at edit distance.