WIP: Energy Performance Preferences

Action managing the CPU's energy performance preference and governor. You can assign values in the System Settings' Power Management profiles and it is also exposed in dbus in rg.kde.Solid.PowerManagement.Actions.EnergyPerformanceControl path

This is a work in progress. I consider the powerdevil part complete, but I still need to expose these settings in the powermanagement dataengine and also add some controls in battery monitor plasmoid to manage these from there as well. In the mean time I would really appreciate if someone could do a quick review my code (I'm warning you that my C++ skills suck). I have some FIXME and TODO comments in some places that I need some advise, but there might be other issues as well.

See also plasma-workspace!197 (closed)

Screenshots