Added --json-attributes option
improved json_attributes printing code smell
Added tests for --json-attributes option
Tests fixed to work with mixlib-config >= 2 (backwards compatible)
Merge pull request #27 from onddo/first_boot_attributes

Add --json-attributes option and fix tests with mixlib-config 2
- updated knife-solo example and added doc link
updated examples
Merge remote-tracking branch 'upstream/master' into private_networking