update to battery plugin and other goodies

[edscott wilson garcia]

The battery plugin now works for FreeBSD with ACPI (5.0-5.1). The fan
state indicator is always off, alas, because there is no access to that
function in the freebsd acpi but the AC switch and temperature indicator
work along with the battery life and percentage. I cannot check the apm
stuff on FreeBSD5.1 because this box does not have any apm.

Other goodie related stuff:
-The memory and swap monitors do not work in freeBSD 5.1. I'll try to
look into the problem.
-The show desktop plugin is quite nice and useful, but it would be nicer
if the show/hide buttons were arranged to occupy less space on the panel
(one row in vertical panel or one column in horizontal panel).
-The minicommand line is very neat, the only thing it's missing is to
run autogen.sh with the current tools (libtool1.5 in particular.)