Added a beginners Python VFA tutorial

[em-blue]

Hi @spinicist, I have:

• made a python tutorial that is more general and for beginners
• corrected a broken link to documentation in the README

Let me know if you'd like any changes to the python tutorial!

[spinicist]

Hello, Thanks for this and sorry for the delay in responding. Between this and a couple of other things, it gave me the motivation to actually finish off a new version of QUIT which is now available on the Releases page.

As part of this, I've expanded the existing T1 mapping notebook. This is now in a separate repo here: https://github.com/spinicist/qipype-binder and it will run on mybinder.org (click the launch button on the repo's README). I used the existing notebook because it simulates the images from the BrainWeb phantom, so it doesn't need people to acquire their own data.

If you'd like to contribute any changes or more Notebooks with other methods, I suggest to do that on the new repo. As a side comment - when contributing a PR good practice is to use git squash or git rebase --interactive to collapse your commits into a small number. It makes the git history easier to read for others.

I'm going to close this particular PR but feel free to discuss further or open a new PR on the other repo.