Merge diverging branch 'master' back into spec-coverage.

Conflicts:
	lib/kitchen/cli.rb
	lib/kitchen/driver/ssh_base.rb
	lib/kitchen/generator/init.rb
Add spec for sleep/retry in SSH#establish_connection.

References #399
Remove safe_yaml config & warnings in Generator::Init.

Blocking code in Command::DriverDiscover removed in
ff1fb8a06d9502f8bb9668e2a81286202f993e74

References #416
Add spec coverage for :chef_zero_port in Provisioner::ChefZero.

References #397
Retroactively apply style/linting to master (style).
Diagnose TravisCI failure.
More visibility into features/rake_tasks.feature failure on Travis.
Merge branch 'spec-coverage' into sersut/windows-guest-support

Conflicts:
	lib/kitchen/command/exec.rb