ensure better error message when expecting an Array, but the content defined is nil
Add pry to development bundle group
Add behavior tests for parameter matchers

Without this patch we don't have good test coverage of the way parameter
matches behave.  This patch addresses the problem by adding examples for
the types of parameter values currently implemented as having
expectations against actual values.
Merge branch 'doc75-fix_nil_array'

* doc75-fix_nil_array:
  Add behavior tests for parameter matchers
  Add pry to development bundle group
  ensure better error message when expecting an Array, but the content defined is nil