dual 7-segment countdown timer code

[T.Jackson]

Most of the PIC-based projects in the Silicon Chip magazine don't make usage
of internal pull ups. I've spent the last 10yrs following the magazine very, very closely. I've spent the last 5yrs contributing projects to them on a part time basis. Never tried using internal pull ups - possibly because of this fact. (By the way, I think they're much higher than 25K)