Add new --sort option

This adds a new `--sort` option to choose the way in which the results
in the speed comparison and the markup exports are ordered.

closes #614
closes #601

src/export/orgmode.rs

@@ -22,6 +22,9 @@ impl MarkupExporter for OrgmodeExporter {
     }
 }
 
+#[cfg(test)]
+use crate::options::SortOrder;
+
 /// Check Emacs org-mode data row formatting
 #[test]
 fn test_orgmode_formatter_table_data() {
@@ -105,7 +108,12 @@ fn test_orgmode_format_ms() {
         },
     ];
 
-    let actual = String::from_utf8(exporter.serialize(&results, None).unwrap()).unwrap();
+    let actual = String::from_utf8(
+        exporter
+            .serialize(&results, None, SortOrder::Command)
+            .unwrap(),
+    )
+    .unwrap();
     let expect = format!(
         "{}\
 | =sleep 0.1=  |  105.7 ± 1.6 |  102.3 |  108.0 |  1.00 |
@@ -159,8 +167,12 @@ fn test_orgmode_format_s() {
         },
     ];
 
-    let actual =
-        String::from_utf8(exporter.serialize(&results, Some(Unit::Second)).unwrap()).unwrap();
+    let actual = String::from_utf8(
+        exporter
+            .serialize(&results, Some(Unit::Second), SortOrder::Command)
+            .unwrap(),
+    )
+    .unwrap();
     let expect = format!(
         "{}\
 | =sleep 2=  |  2.005 ± 0.002 |  2.002 |  2.008 |  18.97 ± 0.29 |