[COOK-3273] Add ChefSpec and MiniTest Chef handler

Signed-off-by: Seth Vargo <sethvargo@gmail.com>
[COOK-1170] Properly merge NTP servers array defaults

Signed-off-by: Seth Vargo <sethvargo@gmail.com>
Fix whitespace
Update .travis.yml

Fixed .travis.yml so it no longer looks for the Rakefile under test.
[COOK-3410] eliminate redundancy

* Ensure idempotence for ntp::undo by removing, only if conflicting state exists in run_list
* Remove redundant, and confusingly named disable recipe, ntp::undo serves this purpose.
* Remove ntpdate recipe.
  - This is not a service, it is _NOT_ a thing to be managed.  This
    recipe only affects the redundant ntpdate-debian command.  There is
    little purpose in disabling a command which is not called from the
    host recipe.

Conflicts:
	recipes/disable.rb
	recipes/ntpdate.rb
[COOK-3410] rm unused template
COOK-3410 - Delete tests for ntpdate and disable recipes
Switched to Rubocop from Tailor, resolved all Rubocop violations.
Trivial change to test Travis picking up pull request for build.
Standardizing .rubocop.yml, Gemfile, .travis.yml, .gitignore, removing Rakefile.
Remove minitest-chef-handler and add Test Kitchen integration tests
Normalize contributing and testing sections
Fix build status badge location [ci skip]
Fix bizarre GHFM rendering
[COOK-3651] Refactor and standardize cookbook

- Added test for ntp.conf contents to verify_installed.bats.
- Cleaned ntp.conf.erb for readability & indentation.
- Refactored the per-platform settings in the default attributes file to minimize the number of attribute changes.
- Switched per-platform attribute case statement to use platform_family. As part of this change, switched default service name string to 'ntpd' instead of 'ntp', updated unit tests accordingly.
- Ensured that Linux hosts would not try to run the windows_client.rb recipe.
- Ensured that Windows hosts would not try to run the undo.rb recipe.
- Updated the README.md for completeness & clarity.
- Renamed CONTRIBUTING to CONTRIBUTING.md.
- Quick update to metadata.rb to add xcp (RHEL variant) to supported OS list. See GH pull request #14.

Signed-off-by: Seth Vargo <sethvargo@gmail.com>
COOK-3636 Allow ntp cookbook to update clock to ntp servers

Adds two new boolean attributes:
node['ntp']['sync_clock'] - When true, this attribute forces the ntp daemon to halt, executes ntpd -q, and then starts the ntp daemon again. This will repeat every Chef run while the boolean remains true.

node['ntp']['sync_hw_clock'] - When true, this attribute runs the command hwclock --systohc on supported operating systems, forcing the hardware clock to sync to the system time. This will repeat every Chef run while the boolean remains true.
COOK-3636 Added tests & clarified README.

COOK-3636 Added tests for new attributes & clarified README.
Update metadata.rb formatting
Version bump to v1.5.0
Version bump to v1.5.1