Fixes a bug where if:

Object.Prop1 changes
Object.Prop1 is being listened for changes, and when Prop1 changes, it causes Prop2 to change
Object.Prop2 change listener doesn't fire properly (it is caught in the buffer)

This is because the way Buffer is implemented internally, it Nexts out the buffer, then re-grabs the Close observable, so any changes created during that window are stuck until the buffer gets closed next time.
Much cleaner fix, that still allows the publish/refcount
Merge pull request #649 from reactiveui/fix_nested_object_change

Fix nested object change