Updated README with contributors and roadmap.
Updated README with contributors and roadmap.

paulot/testem,fotinakis/testem,Addepar/testem,johanneswuerbach/testem,Addepar/testem,fotinakis/testem,testem/testem,johanneswuerbach/testem,Addepar/testem,paulot/testem,bradleylandis/testem,bradleylandis/testem,fotinakis/testem,bradleylandis/testem,testem/testem,Addepar/testem,paulot/testem,johanneswuerbach/testem,testem/testem