RAC - reserving partial half hours

A new capability of the Reserve A Computer booking system - users can book for all remaining time in their allotment for the day.

Here's how it works.

A patron signs on to a computer with her library card and uses a computer for 10 minutes. Then later wants more time.
If she reserves a computer, it will assign her 30 minutes as usual. If she clicks on the Back menu on RAC, then clicks to book again, she reserves a computer for an additional 20 minutes.

In the old version, users could not book for partial half hours.