Add contribution guidance

Add CONTRIBUTING.md that points to the same document in chef-cookbooks
Add mention of the contribution document in the top of the README.md
Merge pull request #39 from claco/contributing

Merged automatically by jenkins after successful build test
version bump
Version Bump to 4.1.3
Merge pull request #40 from rackerjoe/master

Version Bump to 4.1.3
move version out of metadata.rb into VERSION
Merge pull request #41 from rackerjoe/master

Merged automatically by jenkins after successful build test
Merge branch 'havana' of github.com:rcbops-cookbooks/kong

Conflicts:
	metadata.rb