Fix include_json matcher

[benitoDeLaCasita]

include_json matcher can now handle Hash and Array, as well as literals with the == operator

[charlierudolph]

If you are adding some new functionality please add tests.

[skalee]

RSpec runtime dependency cannot be removed — cucumber steps in their current implementation rely on RSpec. See: https://github.com/collectiveidea/json_spec/blob/master/lib/json_spec/cucumber.rb