Feature request: Possibility to connect power meter with pulse output

[vuokko]

I would like to see real power stats. There are not so expensive din rail mountable energy meters which sends 1000 pulse /kWh From that it is trivial to count power and used energy. Some settings would require: pin selection, edge selection and pull-up or pull-down behaviour. Also the ratio should be selectable.

Implementing this shouldn't need much effort.