7z压缩接口封装成控件（内存加载7Z.DLL 无需安装7Z和 7Z.DLL）(7z compress interface in memory)

VC的引用库文件为xxx.lib， GCC的为xxx.a， 通过比较两种库文件的格式，发现很相似。于是把xxx.dll，xxx.lib和xxx.h复制到Qt的project下，直接把xxx.lib改为xxx.a, 根据Qt的库名字的格式， 在xxx.a的前面加上lib， 即为libxxx.a。(The reference library file for VC is xxx.lib, and GCC is xxx.a. It is found to be very similar by comp