Improve link for Python examples

[lesteve]

I find pointing to the folder rather than the README.md is clearer. Note: you still see the README.md at the bottom of the page with the new link.

I was a bit confused when I clicked and only saw the README and thought "but where are the examples I wanted to look at?".

[coveralls]

Coverage remained the same at ?% when pulling 4c0a680 on lesteve:patch-1 into f665f3f on stack-of-tasks:master.

[jcarpent]

@lesteve Good to see you here! Thanks for this contribution.

[lesteve]

I realized you had a devel branch after I created the PR against master. I am guessing I should have targeted devel so maybe there is some cleanup you may want to do at one point.

You may consider adding a CONTRIBUTING.md file at the root of your repo for contribution guidelines. See this for more details.