update dependences
Convert specs to RSpec 3.0.2 syntax with Transpec

This conversion is done by Transpec 2.3.3 with the following command:
    transpec

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

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

* 4 conversions
    from: lambda { }.should
      to: expect { }.to

* 1 conversion
    from: lambda { }.should_not
      to: expect { }.not_to

For more details: https://github.com/yujinakayama/transpec#supported-conversions
Split things in diffrent files
remove deprecations as this is rails 4 branch
move migrations to ActsAsRelation module
add some notes to README
version bump