anal-retentive culling of all dangling whitespace
more idiomatic nil? handling

There are a lot of places that check for `obj == nil` and `obj != nil`.
As `nil` is just an object in ruby, it is often considered more
idiomatic to send the #nil? message to an object to check for nil-ness.

Alos, turn the `if ___ != nil` into `unless __.nil?` in order to be more
consistent
extract getting the duration of a wavefile into a method
I hate setting variables to `nil`
if all AudioUtils is used for is class methods, it is probably better as a module, not a class