Changeset [c198ec308096329e5e6b33304cad58bf20c483c4] by Robert Buels

refactor FeatureTrack

Make it keep its IntervalStore object encapsulated, and delegate
methods to it as appropriate. Also, give it a DESTROY that calls
finishLoad() if a load is in progress, obviating the need to
explicitly call finishLoad() most of the time. Also, make the
encapsulated NameHandler not be created until startLoad() is called.
https://github.com/GMOD/jbrowse/commit/c198ec308096329e5e6b33304cad...