Remove the sony(4) and piixpcib(4) based actions; all powerd(8) scripts
should either be machine-independent or provide hints for the user. Also
clean the script a little.

Enclose the ifconfig commands in $(...) so they actually do something.

Reported on current-users by Pierre Pronchery <khorben at defora dot org>

fix a couple of comments

Add useful example scripts for powerd acadapter, lid_switch, and
sleep_button events. These use the /dev/apm interface, so should be useful
on more than just i386.