Make `update` implicitly run autoconfig and relink
Make `update` implicitly run autoconfig and relink

If the update command is successful and there are changes, rcfiles will
now implicitly run two commands to make sure that any new configuration
changes or linked rc files automatically take effect.

Also, make sure that the relink command returns success (it currently
cannot detect failure)

sycobuny/rcfiles,sycobuny/rcfiles