All driver repos should have a contributing file

[stof]

this file should explain that new features in drivers must first have a test added in the driver testsuite in Mink

[aik099]

While we're at it maybe a README format needs to be changed as well according to http://williamdurand.fr/2013/07/04/on-open-sourcing-libraries/ .

Even though GitHub shows link to CONTRIBUTING.md file on top of each issue reporting screen some people still don't see it. Placing it in README.md would surely make it more visible.

[stof]

Well, we could have a small section in both (and they may link to the official mink documentation which has a first simple chapter about contributing which should be expanded)