rename strand_arrow to strandArrow
factor feature description-parsing logic into its own mixin JBrowse/View/_FeatureDescriptionMixin
fix canvasfeature track label/description not showing in normal displaymode
add a toString to Block objects
make default feature detail popup use getFeatureLabel and getFeatureDescription
Revert "make wigglevaluedisplay flag explicitly say "no data" when
there is no data"

This reverts commit e8948d01a4daaacff8d787373d5d8d0b0b0bd7da.
rewrite NCList synchronization logic to use promises, now finishCallback is actually always called after all featCallbacks
make prepare-refseqs.pl support gzipped gff3 files
fixed prepare-refseqs.pl bug with multiple refseq definitions
add explicit "bytes" in the title of export view dialog to prevent confusion with base pairs
add "Highlighted region" as one of the export choices
fix gff3 export bug
Merge branch 'master' into combination_track

Conflicts:
	src/JBrowse/View/Track/WiggleBase.js