fix Gene glyphs
add another param to event handler callbacks in Glyph tracks that contains an array of all the features and subfeatures that were under a click event
wip implementing JBrowse/Resource base class for tracks, stores, and reference sequence sets
Merge branch '2.x' into reference_panes

Conflicts:
	src/JBrowse/View/FeatureGlyph/Gene.js
	src/JBrowse/View/RegionBrowser2.js