Divide the sums by the weights to get a finished height grid #42

Description

Create a function that returns one grid the size of the region, each cell being its sum divided by its weight.

Testing:

• Assert one window of all fives, with any weights, reads back as all fives inside that window. The answer must not depend on how large the weights were
• Assert two overlapping windows both holding fives read back as fives everywhere including the overlap. If the overlap reads as ten then the division is missing
• Assert two overlapping windows holding different values read back as a mix of the two in the overlap and not one or the other