TribbleListFeatureSource would not work over http
Add command line flag to launch script so IGV is displayed in menu bar on macs
Wrap delete/backspace keys in Globals.isProduction for now

IGV-2022
VCFVariant optimization -- copy sample-genotype map
Make local copies of Tabix reader classes to control buffering.  The only real change here is 2 lines in TabixReader.
Fix minor VariantTrack rendering bugs
Merge remote-tracking branch: upstream/master