Move test_unit integration code to fix warnings.
align code in example with the doc string

- doc string says "expect {}.should", but I changed code
  in a previous commit to "expect {}.to"
Allow a callable object as a custom failure message.
Merge pull request #250 from phiggins/move_test_unit_code_to_fix_warnings

Move test_unit integration code to fix warnings.
Move warning message from its own method.
use new deprecation API
Merge pull request #251 from phiggins/callable_object_as_custom_failure_message

Allow a callable object as a custom failure message.
Merge pull request #253 from rspec/new-deprecation-api

use new deprecation API
convert a cuke to expect syntax
clean up cuke
Prep changelog for 2.14.0.rc1 release. [ci skip]
Release 2.14.0.rc1