---- Changes since 1.140 ----
Moved code for connecting a PPTP tunnel to a separate function, so it can be called by other modules.
---- Changes since 1.190 ----
A PPTP tunnel can now be configured to activate at boot time.
---- Changes since 1.390 ----
When connecting a PPTP tunnel, an optional override password can be entered. This allows you to avoid storing the PPTP password in a configuration file. Thanks to Nicolas Ledoux for this patch.