No longer CC a user by default

Its annoying to CC a user on every change they make through the web
interface, if they performed the change then they know they did it
and don't need a carbon-copy cluttering up their inbox.

Add a user level preference setting to control whether or not we
should CC the user if we are sending an email on their behalf.
By default disable it, because this is a common complaint.

Bug: issue 311
Change-Id: I431cc0e5df34ef44114bf3e5c92c4f2d5e3f0354
Signed-off-by: Shawn O. Pearce <sop@google.com>
8 files changed