Use of interpolation in comparing real/synthetic simulation timeseries

[barneydobson]

I don't think it makes sense to interpolate missing data before computing NSE, I think it makes more sense to just drop those dates and compute NSE for the rest.

Originally posted by @cheginit in #60 (comment)

My concern is that SWMM timesteps can be selected by the solver on the fly (i.e., whether it is dry or not) - and so there is a risk that there will be no perfectly overlapping datapoints if the synthetic and real simulation solvers get out of sync.
However, and probably the intuitive basis of your concern, is that if someone ramped up the DRY_STEP or REPORT_STEP values in the .inp file to increase speed, this interpolation could cause some significant issues.
Ultimately I think this is probably too complicated to fix here and needs its own issue, and ideally some simulations we can look at to see the balance of risks here.