Add examples to documentation

[trainorpj]

I'd like to have basic, illustrative examples in the documentation for each function. I would like each entry in the docs to look like:

getMiddleCols(matrix)

[Whatever the description of getMiddleCols is]

Example:

getMiddleCols()

[[*, 1, 2, 3, *],          [[1, 2, 3],
 [*, 4, 5, 6, *],    -->    [4, 5, 6],
 [*, 7, 8, 9, *]]           [7, 8, 9]]

If you're going to contribute, please only do one at a time. This would go a long way, and it might make a good first contribution 😃