Restart IDLE every 29 minutes

RFC2177 says that servers MAY consider clients inactive after 30 minutes
and recomments clients to re-issue IDLE every 29 minutes to ensure the
connection is kept alive and does not timeout.

This will also ensures that if the TCP connection silently times out,
we will detect that within at worst 29 minutes and restore the connection.

This should hopefully make IDLE more reliable again for everyone.