Create high level schematic of function flow within jmpost

[gowerc]

Need to produce a diagram to accomany the following vignette text:

The design for jmpost is modular; sets of function have specific objectives, which can be broadly categorized as: “Data Preparation”, “Model Fitting and Assessment” and “Sensitivity analysis and Predictions”, as shown schematically in Figure 1.

The following is given as a point of reference / inspiration:
Baio (survHE) Fig.1 ( https://www.jstatsoft.org/article/view/v095i14 )