Add MagickAutoGammaImage and MagickAutoLevelImage

tests/lib.rs

@@ -396,3 +396,23 @@ fn test_resource_limits() {
     let wand = MagickWand::new();
     assert!(wand.read_image("tests/data/rust.png").is_ok());
 }
+
+#[test]
+fn test_auto_level() {
+    START.call_once(|| {
+        magick_wand_genesis();
+    });
+    let wand = MagickWand::new();
+    assert!(wand.read_image("tests/data/IMG_5745.JPG").is_ok());
+    assert!(wand.auto_level().is_ok());
+}
+
+#[test]
+fn test_auto_gamma() {
+    START.call_once(|| {
+        magick_wand_genesis();
+    });
+    let wand = MagickWand::new();
+    assert!(wand.read_image("tests/data/IMG_5745.JPG").is_ok());
+    assert!(wand.auto_gamma().is_ok());
+}