Change to be codec to allow "zero" values for thick start & end
Change to be codec to allow "zero" values for thick start & end

amwenger/igv,igvteam/igv,amwenger/igv,amwenger/igv,igvteam/igv,igvteam/igv,amwenger/igv,amwenger/igv,igvteam/igv,igvteam/igv