Only Linux provides detailed energy statistics. The BSDs directly
provide percentage values. This change makes it easier to split
out the BSD code and reduces code overhead on BSD systems.
Instead of returning a const string, that is fed into strdup, tooltip
functions are now supposed to return allocated strings. This fixes a
memory leak in the battery tooltip.
This is used instead of simply freeing the memory in the battery
tooltip function, since it also avoids a uselesss strdup().
This adds a new config option 'battery_tooltip' (enabled
by default), which can be used to enable a tooltip for
the battery widget providing details for all installed
batteries.
Some notebooks, like the ThinkPad X240 and X250 have two batteries
installed. So far only one of the batteries have been checked by
the tint2 widget making it more or less useless on those systems.
After this patch tint2 will aggregate the data from all batteries
instead.
