Added notes to GenIncProcess examples
Added notes to GenIncProcess examples

When run, ConsGenIncProcessModel.py examples now display notes about the construction of pLvlGrid and why ExplicitPermInc generates a consumption function that deviates from the more accurate solution in ConsIndShock.  Feels very text-y, but will look better when these examples are moved into Jupyter notebooks.

econ-ark/HARK,econ-ark/HARK