download link for example.jemdoc without menu setup

[zhl355]

Thanks for writing this great tool. Here are some minor issues I encountered when I tried to run a example.

• It will great to include a download link for example.jemdoc without menu setup. So new beginner can quickly test it more easily by just typing jemdoc example.jemdoc

• It will be better to have a python 3 revision since python 2 is outdated.