QT下树节点,在QT下实现树节点的功能。测试能正常使用-QT under the tree nodes, the QT under the tree nodes function. Testing normal use

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)