mail header to prevent out of office replies

[Robert Marianski]

We should add a header on mail messages to signal that auto responses, like out of office replies, should not get sent out.

I've verified that adding a "Precedence: Bulk" header suppressed outlook out of office replies. But, that is discouraged by rfc 2076. I've seen it suggested on stack overflow that a null return path might be a better alternative (Return-Path: <>), but I'm not sure what the consequences of that are. Generally, we have most of our issues with outlook anyway, so it may be safer to use the precedence header even if it isn't a standard.

[JimPGlenn (jpglenn09)]

fixed