NRE fixes and chute warning toggle.

This fixes some holes that produce NREs and also provides a toggle for the parachute warning.

The warning is a nice feature for newbies, but there are a great many of us that really do not need it, so being able to turn it off is very nice. Note that if the option is turned off while the message is displayed, it will take a second (longer if frame rate is poor) to disappear.