added real "open with" support

src/Ation.js

@@ -28,7 +28,7 @@ class Ation {
 
 		app.whenReady().then(async () => {
 			if (this.fileToOpen)
-				dialog.showMessageBox(this.windowManager.mainWindow, {message : this.fileToOpen});
+				this.openFile(this.fileToOpen, true);
 			protocol.registerFileProtocol("slideimg", (request, callback) => {
 				const uri       = request.url.replace(/^slideimg:\/\//, "");
 				const extension = path.extname(uri).replace(/^\./, "");