added DPMS "management" (disable during inhibit, enable afterwards)
updated changelog
Merge branch 'dpms'

Sometimes other things will re-enable DPMS even though Caffeine disabled it, e.g. by /etc/acpi/lid.sh (when the user opens the laptop lid). It's probably better to fix this in Caffeine, but I figure this might help others who aren't using Caffeine.
increment version
extended copyright