lots of work starting to implement revised ui mockup
make regionbrowser track panes scrollable in Y
remove some files that are not used in 2.x
add the beginnings of a reference set pane that groups views that use the same reference set as the basis for their projections
style the reference set pane more
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
start of datahub manager, with a tree view
more work on datahub manager. ditching tree for titlepanes for each type of resource, containing dgrids
more work on data hub mgmt gui
more work on datahub manager
style datahub manager a bit
add fadeIn/fadeOut for datahub manager
more datahub mgr styling
make menubar styles more SCSS and tweak a bit
tweak titles of data hub-related ui
remove combination track functionality for now, will need to be ported over sometime in the future
add Help button, remove help dropdown menu
fix `about` dialog
add combobox ref set selector to reference pane header