some tweaks/fixes/etc to the map preview and reload stuff
also fixed an old bug of a "stuck random/drawn map preview" when changing maps quickly
#include <QApplication>
#include "mainform.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MyWindow *mainWin = new MyWindow;
mainWin->show();
return app.exec();
}