Show graph and units

[trsqr]

Currently the counters in the UI will be shown without units and also when you click the items you cannot see historical data.

Here an example, no units (compare to my Aquarea air-water heat pump sensors for example):

For example, water pressure is shown like this when I click it:

Whereas I would like to see something like this:

[gkreitz]

Thank you for this feature request!

I've now set unit_of_measurement on the sensor entities, which should give you the requested graphs.