進入qt世界的第一隻程式，使用qt creator！-To enter the the qt world s first only program using qt creator!

Qt快速入门中的helloworld源码，在对话框中显示helloworld的字样。-Qt quick entry in the HelloWorld source code, in the dialog box shows the word helloworld.

拿来验证qt环境是不错的，测试过win10+Qt4.8.0 + Qt Creator 2.4.1 + mingw4.4.0，linux3.2+qt4.8.3(Used to verify qt environment is good, tested win10 + Qt4.8.0 + Qt Creator 2.4.1 + mingw4.4.0, linux3.2 + qt4.8.3)