LessSource

With reference to issue #92.

I've tidied up the indentation to match (I hope) and undone some of the accidental changes I made (optimize imports in Eclipse).

I've submitted this as a Pull Request as hopefully it will make it easier to see what I've changed and added.

In future, other subclasses of LessSource can be used transparently to the rest of the code-base, which I think is a pretty neat feature of the change!

Best regards,
Karl