Fixed segfault in QApplication::exec by copying argc and argv into ui class

also reenabled writing to the QPlainTextEdit

ui.cpp

@@ -1,7 +1,9 @@
 #include "ui.h"
 
 ui::ui(int argc, char **argv) {
-	app = new QApplication(argc, argv);
+	this->argc = argc;
+	this->argv = argv;
+	app = new QApplication(this->argc, this->argv);
 	mainWindow = new QWidget();
 	mainWindow->resize(1280, 720);
 	mainWindow->setWindowTitle("oksirc - early Qt test");