Remove trailing whitespace.
wmbattery: Remove Debian-specific distribution and urgency from ChangeLog.
wmbattery: Add -x option to run a command when battery is critical.

This is based on the patch by Cristoph Fritz submitted to Debian.  See
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=543674
wmbattery: Consistent formatting in source.

Modified source files to minimize warnings from checkpatch.pl in Window Maker
source tree.
wmbattery: Add copyright header to source.

Copyright information used to be in debian/copyright, which was removed
upstream.
wmbattery: Add -v option to display version number.

Also, in order to facilitate this, keep track of version number in configure.ac.
It was previously only mentioned in ChangeLog.
wmbattery: Restore BSD support.

Code that was ripped out of wmbattery for version 1.22, which introduced the
dependency on libapm but dropped support for the BSDs, has been restored.
wmbattery: Bump to version 2.45.