Input data with non-hourly resolution

[jwohland]

demand-ninja/demand_ninja/core.py

Line 164 in 248c32c

I was a bit confused when trying to use demandninja with daily data. It didn't throw any errors but reported NaNs. It's clear from the variable description that demand ninja expects hourly data. However, maybe one could add a

assert df.index.freq == "1H"

in the function definition to save other climate folks some time who might also want to use it with different timesteps.