Re:Intervals vs Span guidance

[Ramsey Haddad (BLOOMBERG/ LONDON)]

For anyone interested, Alan Woodward responded to the copy of this that I 
posted in the dev mailing list.

https://lists.apache.org/thread.html/e0c8f97211efa1c7445ac2514d4ff0570953ded4a723c81338b41b94@%3Cdev.lucene.apache.org%3E