spike: compare imod-python transport splitting with flopy transport splitting.

[luitjansl]

In the 1d transport model that we used there is a numerical error in concentration results when comparing the split simulation with the unsplit simulation. We should investigate why this is.

We can compare our transport model splitting with that of flopy.

1. import the unsplit 1d example into flopy'
2. split it with flopy
3. split it with imod-python
4. compare input and output of the flopy and imod-python split simulations

[luitjansl]

closed, because 1) the cause of the mismatch between concentrations of the unsplit model and the split model were due to a typo in the comparison check. Time 2000 for the unsplit model was compared to time 200 of the split model. 2) when testing with flopy, for the test simulation it was found that flopy could split it, but the transport model was not in the final split simulation, making the comparison impossible.