broesler's version of README.md missing useful information that exists in wmvanvliet's version

[tcmulcahy]

In particular, I found the section on "First, we need to configure the jupyter console and qtconsole clients to display output from other clients" useful and I struggled to figure out how to do this. Later, I discovered that it was already documented in wmvanvliet's version.

This is sorta implicitly documented in https://github.com/broesler/jupyter-vim/blob/master/doc/jupyter-vim.txt (in the "JUPYTER-VIM VS. VIM-IPYTHON" section), but I think it should be much more prominent.