Validate keys parameter

Ensure that keys is a hash
Merge pull request #35 from ghoneycutt/validate_keys_hash

Validate keys parameter
Release v3.2.1

Validates keys parameter to ensure it is a hash before calling
create_resources().
Add test for ssh key that runs a command
Add example of ssh key running command to README
Change default value for sshd_config_challenge_resp_auth to 'yes'
Merge pull request #36 from dantremblay/CRA_yes

Change default value for sshd_config_challenge_resp_auth to 'yes'
Release v3.3.0 - Default ChallengeResponseAuthentication to yes

This is the default given in SSHD_CONFIG(5)
Add option to specify banner content
ssh_config_hash_known_hosts option added
fixing spec warnings
Merge pull request #38 from Phil-Friderici/ssh_config_hash_known_hosts

ssh_config_hash_known_hosts option added
Add ability to manage HashKnownHosts in ssh_config
Merge pull request #39 from Phil-Friderici/spec_test_fixes

fixing spec warnings
Add checks to `rake validate` and update Travis
Update to work with new version of rspec-puppet
Clean up contributions and improve spec tests
Cleaning up contributions
Merge pull request #40 from ghoneycutt/add_banner_file

(#244) Add banner file
Release v3.5.0 - Optionally manage banner file