Adding solution code with comments

Added the folder SolutionsWithComments, which contains commented solutions to the exercises from the workshop. This code is largely based on Christoffer's code found in folder Solutions. But I've added tons of comments and have used slightly different functions and code for some of the questions. I've created a different folder from Christoffer's because I think it's pretty helpful to have both to compare. However, please add comments/correct my code directly.