Adds the ability to read gzip-tar file for the taxonomy dump

pkg/obiutils/tar.go

@@ -0,0 +1,20 @@
+package obiutils
+
+import (
+	"archive/tar"
+	"fmt"
+)
+
+func TarFileReader(file *Reader, path string) (*tar.Reader, error) {
+	tarfile := tar.NewReader(file)
+	header, err := tarfile.Next()
+
+	for err == nil {
+		if header.Name == path {
+			return tarfile, nil
+		}
+		header, err = tarfile.Next()
+	}
+
+	return nil, fmt.Errorf("file not found: %s", path)
+}