DREAM fluxes are slow to examine in GUI

[peterson-tim-j]

Examining model_TFN soil model fluxes from DREAM calibration within the GUI is currently very slow (V0.14). This is because the soil model is re-run for each parameter set each time the model is selected within the GUI. This creates a poor user experience.

Ideally, examining DREAM fluxes should be very inefficient. If the soil ODE was faster to solve (issue #55) and the getTransformedForcing() was vectorised for multiple parameter sets, this issue may be resolved. However doing so would still require >16+GB of RAM for 10,000+ DREAM parameter sets.

Any thoughts on this are welcome.