drop deprecated usage of Guard::Guard
add and use gem-bundler
add transpec
Convert specs to RSpec 2.99.2 syntax with Transpec

This conversion is done by Transpec 2.3.7 with the following command:
    transpec -f

* 54 conversions
    from: obj.should_receive(:message)
      to: expect(obj).to receive(:message)

* 38 conversions
    from: obj.should
      to: expect(obj).to

* 18 conversions
    from: == expected
      to: eq(expected)

* 9 conversions
    from: obj.stub(:message)
      to: allow(obj).to receive(:message)

* 5 conversions
    from: be_false
      to: be_falsey

* 5 conversions
    from: obj.should_not_receive(:message)
      to: expect(obj).not_to receive(:message)

* 3 conversions
    from: be_true
      to: be_truthy

* 1 conversion
    from: RSpec.configure { |c| c.color_enabled = something }
      to: RSpec.configure { |c| c.color = something }

For more details: https://github.com/yujinakayama/transpec#supported-conversions
bump rspec to 3.1
add guard-rubocop with config for HoundCI
remove project-wide rubocop offenses
update spec config
Merge pull request #11 from guard/overhaul

Overhaul