Do the sensor setters in two stages

When saveConfig() in ConfigSensors.qml is called we started resolving sensors, when during this time loadConfig() was called we returned the old sensors, which when then triggeded another saveConfig() call by plasma-systemmonitor leading us to effectively reset ourselves. The setters are now in two stages, during resolving time we set the properties to the unresolved value, so we are in sync with what the qml part did. Also we not do another resolve when something tries to set the current unresolved ids. BUG:432254