Display: No padding if no bars drawn

If not drawing the percent bars do not add padding to the filenames
https://github.com/bootandy/dust/issues/89

tests/tests.rs

@@ -32,6 +32,16 @@ pub fn test_basic_output() {
     assert!(output.contains("a_file "));
 }
 
+#[test]
+pub fn test_output_no_bars_means_no_excess_spaces() {
+    let mut cmd = Command::cargo_bin("dust").unwrap();
+    let output = cmd.arg("-b").arg("src/test_dir/").unwrap().stdout;
+    let output = str::from_utf8(&output).unwrap();
+    // If bars are not being shown we don't need to pad the output with spaces
+    assert!(output.contains("many"));
+    assert!(!output.contains("many    "));
+}
+
 // "windows" result data can vary by host (size seems to be variable by one byte); fix code vs test and re-enable
 #[cfg_attr(target_os = "windows", ignore)]
 #[test]