Fix .gitignore entries that weren't being parsed. Fix inconsistent indenting and whitespace.

[jgreenemi]

Hey there - while reading through the code I kept tripping over spacing inconsistencies that made it distracting to read through. I've updated spacing and indenting to be consistent with the PEP8 standard. The logic of the code remains unchanged. I did not review the contents of code cells in the Jupyter notebook for formatting inconsistencies.

Also, the .gitignore looked to have been copied in from somewhere that introduced a preceding - string to each line (aside from the custom lines at the bottom), rendering the entries unusable. I've fixed these lines so now virtualenv directories, compiled Python files, etc. will not be included in future git commits. I did take the liberty of adding an Intellij-specific ignore rule for the .idea/ preferences directory as is standard practice.

Do let me know if I can answer any questions, or if splitting this into separate PRs will help given that the size of the change is not trivial.

All the best,
Joe.