#66 use of smtp leads to race conditions

[Colin McCormack]

The tcllib smtp server is now used for email from the
server, however smtp contains a vwait which opens the
server to new http connections and interactions on
already-open sockets.

This can lead to race conditions in a non-threaded
tclhttpd whenever an email is sent.

Possible resolution: a proc to suspend processing of
all existing connections and all new connections until
the smtp process has completed.