Fixed case where items are equal under the sort passed to an IncrementalResult, but the items are still unique items, and should both be added to the sort. Duplicates should only be ignored when they are reference equal.
Changed not accepting objects with equal hash codes that are not reference equal..
Fixed a bug with the last fix. And added a test to make sure it's actually fixed right this time.
Merge pull request #57 from stravant/master

Fixed IncrementalResult not working with equal items.