[iagno] Add aliases to command-line level.

[Arnaud B. <arnaudb src gnome org>]

commit 0b9881a666821ea8a081532b3b87e72e038a8fe4
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Thu Feb 7 12:04:15 2019 +0100

    Add aliases to command-line level.
    
    These are implied by the error
    message anyway, just add them.

 src/iagno.vala | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/src/iagno.vala b/src/iagno.vala
index 358234b..50b677c 100644
--- a/src/iagno.vala
+++ b/src/iagno.vala
@@ -177,13 +177,16 @@ public class Iagno : Gtk.Application
             switch ((!) level)
             {
                 case "1":
-                case "one":     settings.set_int ("computer-level", 1); break;  // TODO "easy"
+                case "easy":
+                case "one":     settings.set_int ("computer-level", 1); break;
 
                 case "2":
-                case "two":     settings.set_int ("computer-level", 2); break;  // TODO "medium"
+                case "medium":
+                case "two":     settings.set_int ("computer-level", 2); break;
 
                 case "3":
-                case "three":   settings.set_int ("computer-level", 3); break;  // TODO "hard"
+                case "hard":
+                case "three":   settings.set_int ("computer-level", 3); break;
 
                 default:
                     /* Translators: command-line error message, displayed for an incorrect level request; 
try 'iagno -l 5' */