Remove unnecessary data property

This reduces the need to always look up osu properties via the data
property, the properties can now be accessed directly on the OSUFile
object.
Add additional file system utility function
Fix circle sizes to equal the official size more

Need to check the correctness of the formula though.
Use the new utility function
The circle borders are completely white in osu!
First implementation of a storyboard

The storyboard currently only initializes the background.