Shorter intro & comments on screenshots
Shorter intro & comments on screenshots

- shorter intro back #52 
- comments on screenshots #51
- feedback welcome
mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext