GlobalVariables additional documentation/notes

When upgrading from vCheck 6.18 -> 6.20-alpha-1, email functionality was
changed slightly.  Previously, you could list multiple To addresses in
the format: "me@mydomain.local","me2@mydomain.local"

With the new changes this doesn't work.  Added notes to give a proper
example: "me@mydomain.local,me2@mydomain.local"