利用SetClassLong函数给nsis窗口添加了阴影，看起来很酷^_^
System::Call `user32::SetClassLong(i$HWNDPARENT,i${GCL_STYLE},i${CS_DROPSHADOW})`SetClassLong
Replaces the specified 32-bit (long) value at the specified offset into the extra class memory or the WNDCLASSEX structure for the class to which the specified window belongs.
Note This function has been superseded by the SetClassLongPtrfunction. To write code that is compatible with both 32-bit and 64-bit versions of Windows, use SetClassLongPtr.
SyntaxDWORD WINAPI SetClassLong( __in HWND hWnd, __in int nIndex, __in LONG dwNewLong);
