ENH: Add markdown formatted README and LICENSE and update acknowledgements

Acknowledgements have also been updated in NIH format

http://grants.nih.gov/grants/acknow.htm

using the list on public wiki

http://public.kitware.com/Wiki/TubeTK/About

Change-Id: I191c3da0c0047a1cabd90640b5295e748843b5f1
Merge topic 'MarkdownReadMe'

6e18f80 ENH: Add markdown formatted README and LICENSE and update acknowledgements