#10 Check for updates vigorously after startup

[Keith Lea]

The Scheduler checks for updates to course DB,
configuration files, icons, and other resources on
startup. However, it times out quickly to improve
startup time.

The Scheduler should check for updates to these things
while the Scheduler is running, and save them for next
start, or ask the user and re-load them, if possible.

The Scheduler should also check for program (JAR)
updates, and install them at the user's request.