Delphi禁止运行程序多个实例，程序先初始化参数，然后判断程序是否已经运行，得到程序的句柄，若发现多个句柄，就只运行一个句柄，程序也就始终保持一个窗口。-Prohibit running multiple instances of Delphi program, the program first initialization parameter, then judge whether the program is already running, get the program handle