Write the equality result class

[craigfowler]

This class needs to be a collection of equality rules, as written in #1. This class will be immutable.

It should be created by a factory, which will also be written as part of this ticket. That factory will take a collection of rule objects and will create the overall result type.

The result class will have:

• A property which lists all of the rules executed (their results)
• A property which indicates whether the result indicates equality or not

The factory needs one method:

• Create an equality result from a collection-of-collections of rule results.

It should merge all of these collections and create a result which just has a single collection of results. It should throw an exception on duplicate rule names.

[craigfowler]

Another part of this is to write the function on the parent equality rule, which gets an equality result.