Simple use case examples to resolve #373

[jakepalmer]

I've put together some example use cases as suggested in #373 by @dbkeator. I've included a single T1 nifti (my own defaced scan so no problem with permissions/privacy etc) to enable users to simple clone and copy/paste commands from the README. I can re-work if inclusion of data like this isn't ideal for any reason.

[kaczmarj]

this is really great -- thank you @jakepalmer.

i've been inactive here for a while, but i'm back now. we have a website now at https://www.repronim.org/neurodocker/ and this would fit really well there. could you please add these things to docs/ -- wherever you think they make sense.

[djarecka]

@jakepalmer - thank you for your PR and sorry for late reply.

@kaczmarj @satra - I found this old PR that adds additional use cases for working with data. This PR adds also scripts to docs, so I'm not sure if we want to merge it in this form. Any thoughts?

[kaczmarj]

instead of storing the data and scripts in this github repo, i would prefer to include a download command to get sample nifti files, and to maybe paste the scripts into the common_uses.rst file itself. otherwise this looks great.

[stebo85]

agree with @kaczmarj that the example file shouldn't be in the github repository.

@jakepalmer could you change this example to a download link and update the pull request?