Use transpec
Convert specs to RSpec 2.99.2 syntax with Transpec

This conversion is done by Transpec 2.3.6 with the following command:
    transpec

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

* 5 conversions
    from: be_true
      to: be_truthy

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

* 2 conversions
    from: be_false
      to: be_falsey

* 1 conversion
    from: == expected
      to: eq(expected)

* 1 conversion
    from: Klass.any_instance.should_receive(:message)
      to: expect_any_instance_of(Klass).to receive(:message)

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

* 1 conversion
    from: obj.should_not_receive(:message)
      to: expect(obj).not_to receive(:message)

For more details: https://github.com/yujinakayama/transpec#supported-conversions
Cleanup Guardfile
Use RSpec 3.0
Remove bundler from gemspec
Merge pull request #15 from katsuma/upgrade_rspec3.0

Upgrade rspec3.0