rename bc-template-foo.schema to attributes.schema

Add roles section to template deployments
Merge pull request #20 from VictorLowther/pull-req-master-9bdf40d9e246f0feb72ee603555057fa7d132fd9

https://github.com/crowbar/barclamp-hadoop/pull/20

Merged by devtool for VictorLowther
Update and rename README.txt to README.md