Add Readme.md, contributing.md

[jimmyDunne]

Repo will need some structure as more people contribute files. Some guidance on naming conventions, and c3d contents (de-identified data especially) should be included.

[pariterre]

Yep I agree,
Do you have an example that I could copy the structure. When I created the repo earlier, I started to create folders and I could not figure in advance how I should put them to account for pushes from other... So for now, I just put them directly in the first folder... :S

[jimmyDunne]

I will make a pull request next week with some suggestions— that way we can iterate and discuss with some working examples.