Show unused parameters in command names

closes #600

src/export/csv.rs

@@ -62,6 +62,7 @@ fn test_csv() {
     let results = vec![
         BenchmarkResult {
             command: String::from("FOO=one BAR=two command | 1"),
+            command_with_unused_parameters: String::from("FOO=one BAR=two command | 1"),
             mean: 1.0,
             stddev: Some(2.0),
             median: 1.0,
@@ -80,6 +81,7 @@ fn test_csv() {
         },
         BenchmarkResult {
             command: String::from("FOO=one BAR=seven command | 2"),
+            command_with_unused_parameters: String::from("FOO=one BAR=seven command | 2"),
             mean: 11.0,
             stddev: Some(12.0),
             median: 11.0,