Merge branch 'master' into stable

* master: (41 commits)
  Update packaging to use install.rb
  (maint) Add acceptance setup steps from puppet-acceptance
  Fix the spelling of exactly
  Fix typo: intreprets => interprets
  Move interpolation to a separate class
  Change get_interpolation_method_and_key to private
  Add Hiera::InterpolationLoop exception class, use rather than raising a generic exception
  Add a Backend.clear! method to remove any initialized backends
  Collapse SCOPE_INTERPOLATION & HIERA_INTERPOLATION into a single regex, use Matchdata objects rather than Perl style variables.
  Add support for a hiera variable syntax which interpolates data by performing a hiera lookup:
  Set backends to nil before loading a backend
  Remove trailing whitespace in deep merge comment
  Revert "Merge pull request #137 from lollipopman/add_hiera_lookup"
  And one more line inconsistent
  Fixed configuration example consistency problem
  (22329) Only delete hiera files in the preflight
  Update for new osx packaging target
  (21868) Move hiera libary target to /Library/Ruby/Site
  (#22142) Ensure that :datadir is a String
  (Maint) Clean up specs
  ...
(packaging) Update VERSION to 1.3.0-rc1
Merge tag '1.3.0-rc1'

1.3.0-rc1

* tag '1.3.0-rc1':
  (packaging) Update VERSION to 1.3.0-rc1