possible values for the wakeup-batteries-capacity register. Add a
few more values i've obtained from my SmartUPS 1400.
Also, make apc.c print out the name of the register in case some
`tune' operation for an APC_TOGGLE type register failed, so the
operator gets a clue about what went wrong.
Maybe i'll someday even find the time to write up a short man page
for all this...
