KITCHEN-75 - support cross suite helpers.

- If there is a test/integration/helpers directory then copy the contents of the test framework specific sub folder
  to the remote suite dir.

For example,

  test/integration/helpers/serverspec/spec_helper.rb

would be copied to /opt/busser/suites/serverspec/spec_helper.rb

This allows common files used across suites (such as spec_helper) to live in one place.
Merge pull request #134 from RallySoftware-cookbooks/KITCHEN-75

KITCHEN-75 - support cross suite helpers.