gui: Fix dispatch of SandboxedProcessor

There was an off-by-one, the SandboxedProcessor was only passed
'process', not the path to the file.

No processor was found for 'process', thus 'nothingProcessor' was
returned. Therefore, we never sandboxed (because we never had
to process anything).

The sandboxing would have failed though, because we need to launch
QCoreApplication, not QApplication.

The CLI was never affected.

gui/main.cpp

@@ -89,16 +89,16 @@ int main(int argc, char *argv[])
 		if(arg == "process")
 		{
 			Common::setupAppInfo();
-			QApplication a(argc, argv);
+			QCoreApplication a(argc, argv);
 
 			QStringList args = a.arguments();
-			if(args.length() < 1)
+			if(args.length() < 3)
 			{
 				qDebug() << "Filename is required";
 				return 1;
 			}
 
-			QString file = args.at(1);
+			QString file = args.at(2);
 			SandboxedProcessor processor(file);
 			return processor.process();
 		}