Make formatting and syntax changes.

I've made some basic syntax and formatting changes. It looks like I've changed a lot of stuff, but it really isn't that many changes. Some of the highlights:

  * I changed tabs to spaces. It is generally considered good practice when using Python to indent code using four spaces. I converted the code here. @CheyenneLaue remind me and I can show you how to set up your editor to use spaces instead of tabs by default.
  * Method names and local variables generally start with a lowercase letter. This helps to distinguish classes from instances of classes and other variables.
  * It is common to follow the method name immediately with the opening parenthesis. This is not true for all languages and styles, and certainly different people prefer different styles, but this is the most common style in Python.

### Using a pull request

You can click on the "Files changed" tab above to see the changes that this pull request has made. Green means something added, read means something deleted. If you hover your mouse cursor in the left margin a little work bubble will pop up, this lets you make a comment on a specific line that others can see. This lets us easily discuss the specific changes the pull request has made. Note that the pull request won't show you the entire file, just the sections that have changed. You can also add a general comment in the "Conversation" page below.
A better name for this might be `cluster` or `congregate`, to make it a verb.