Added block property to block's div (block.domNode),  so can easily retrieve block itself if have block's div. 
Needed for WebApollo traversal of feat -> featdiv -> blockdiv -> block.
make perl pipeline explicitly specify storeClass in n FeatureTrack output
make prepare-refseqs explicitly include the storeClass in the trackList.json entry it makes
Merge branch 'master' of github.com:GMOD/jbrowse
clean up domNode.block pointer when blocks are cleaned up
Fixed typo in ExportMixin causing track data not to be saved correctly
Add display modes 'pack', 'squish' and 'dense' to CanvasFeatures
Added display mode selection to CanvasFeatures context menu
removed unnecessary code from BlockBased.js and fixed checkbox error in CanvasFeatures context menu
make rect layout tweak its pitchY for squished mode, rename pack/squish/dense to normal/compact/collapsed
fixup
also modify the pitchX of the layout when in compact display mode
don't bother connecting mouseover events in canvastracks when in collapsed display mode
add layout options to release notes
don't let layout pitches round all the way to 0
make box glyph not clear its area if in collapsed display mode
suppress uninitialized-value warnings for source-less features in flatfile-to-json.pl when filtering for a certain source
Merge branch 'maint/1.9.x'
fix small bug with placement of highlighting icon in commonIcons*.png
tweak Simple tracklist tracklist-labbel styles, make the inactive track labels look less like buttons