Update README.md with 2.2.0 version numbering

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@palm.com)
Merge commit '2c19b88'
Update package.json with 2.2.0 version

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@palm.com)