exclude/include can now be an array

the most important change here is probably:

* simplify options handling by using ~functions~
Merge pull request #53 from igalic/mult-excl-incl

exclude/include can now be an array
Convert specs to RSpec 3.1.7 syntax with Transpec

This conversion is done by Transpec 3.0.3 with the following command:
    transpec

* 55 conversions
    from: it { should ... }
      to: it { is_expected.to ... }

* 9 conversions
    from: it { should_not ... }
      to: it { is_expected.not_to ... }

68 deprecation warnings