Implement Butterworth filters

src/main/java/presenters/NavPresenter.java

@@ -50,6 +50,11 @@ public class NavPresenter {
         navigator.showFiltering();
     }
 
+
+    public void gotToButterworth() {
+        navigator.showButterworth();
+    }
+
     public GrayScaleMatrix getImageGrayMatrix() {
         return appState.getImage().toGrayScale();
     }
@@ -57,4 +62,5 @@ public class NavPresenter {
     public void setMode(Mode mode) {
         modeService.setMode(mode);
     }
+
 }