Local variables are one of the things CoffeeScript doesn't compile to
modern JavaScript automatically: it uses `var` instead of `const` or
`let`.
Besides, using `$this = $(this)` is usually done to reference the
current object in another function where the current object is a
different one. Here we were using it with no clear purpose.
The `initialize` functions don't need to return anything, since their
returned value is never used.
Returning false is a common practice in jQuery to stop an event, but in
plain JavaScript methods it doesn't have any side effects.
