[Cdash] New Wiki page for email notification

[Trevor Kellaway]

Julien,

> BTW, I'm still having trouble getting "Email me when my 
> checkins are breaking the dashboard" working. 

Looking at sendemail.php, it looks like there is no support for
continuous build email there!

There is only one processing loop on a SELECT "user2project.emailtype>1"
which processes the Nightly/Any errors, but no code to cope with
"emailtype==1" (continuous).

This explains why it isn't working ;-)

-Trev