FreeBSD support

[coreone]

• Add shells support
• Add custom ownership, group, and permissions settings for nsswitch.conf as well as defaults for each OS in params.pp
• Fix ordering for Solaris defaults in params.pp and add missing defaults
• Update README file
• Update Gemfile to use rake < 11.0 to fix Travis failures
• Update .travis.yml metadata lint command
• Fix lint errors in metadata.json
• Correct ruby version mismatches with Puppet 4
• Fix typo in spec file

[coreone]

@trlinkin Let me know if anything else needs to be done to get this merged in. Thanks!