Fixed another drag ghost bug with extra subfeature divs in drag ghost.
Added getSequenceTrack() method to WebApollo plugin main.js
Modified feature dragging setup to handle cases where no AnnotTrack or SequenceTrack is present.  
Although may want to just turn off dragging entirely if no AnnotTrack present?
Modified DraggableHTMLFeatures default config so that start_codon and stop_codon are not rendered.
Added TrackConfigTransformer.js, which handles track config modifications to make JBrowse track types into equivalent WebApollo track types (HTMLFeatures ==> DraggableHTMLFeatures), etc.
Modified main.js to use TrackConfigTransformer to handle track config JBrowse ==> WebApollo transforms
Fixed problem with StaticChunked store setup in WebApollo SequenceTrack when using with JBrowse 1.9.8+
Eliminated distintion between DraggableHTMLFeatures getUIGenomeCoord() and getGenomeCoord(), due to getUIGenomeCoord() fix getting pushed down into GenomeView.absXtoBp() in GMOD/JBrowse 1.9.8+ via commit 76b6a2f09
Added TrackConfigTransformer entry for JBrowse/View/Track/Sequence ==> WebApollo/View/Track/AnnotSequenceTrack
Turning off some diagnostic console output.
Added handling of WebApollo SequenceTrack transformed from JBrowse SequenceTrack config entry. Was problematic due to store config cloning prior to plugin getting access to config. Also handling legacy case where WebApollo SequenceTrack explicitly set up in config entry.
Forcing default feature style to be taller.
Restored WebApollo larger arrowheads