Added POWER_SAVE Notification

[shinyone]

Added POWER_SAVE Notification to alert other modules

[shinyone]

I thought it might be useful for other modules to benefit from the MMM-PIR-Sensor module and can react accordingly.

• Added POWER_SAVE socket notification when the monitor is actually being turned on or off (to avoid too many notifications). USER_PRESENCE is called too many times, then modules can be in sync rather tan each having their own timer.

• Added POWER_SAVE to module which sends it to other modules when recieved.

• Added console log for GPIO pin, that help me solve a problem - thought it might be useful for others.

• Fixed trailing semi-colons that my IDE found.