VariablesTable fixed

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C4215
"mail.add_x_header"
- configuration option added (see Deployement/Web.Config for details)
- 'X-PHP-Originating-Script' mail header not sent by default

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C4219