Add support for bedGraph.gz files (#1)

* Add support for bedGraph.gz files

* check lowercase `bedgraph.gz`

Author: mikecormier

cmd/check-sort-order/main.go

@@ -58,7 +58,7 @@ func main() {
 
 	if strings.HasSuffix(args.Path, ".vcf.gz") {
 		checkVCF(args.Path, gf)
-	} else if strings.HasSuffix(args.Path, ".bed.gz") {
+	} else if strings.HasSuffix(args.Path, ".bed.gz") || strings.HasSuffix(strings.ToLower(args.Path), ".bedgraph.gz") {
 		checkTab(args.Path, gf, get_vcf_chrom_start)
 	} else {
 		found := false