Currently they both are QHash typedefs, which means they are the same thing for the
compiler. For this reason if we pass a CompressionOptions object where an
ExtractionOptions object was expected, the code compiles file even if this is a
major design flaw. Currently we have at least a couple of such bugs, so let's fix
them all by using proper types.
While at it:
- The default value for the PreservePaths option was false, now is true because it's the more common case.
- The RemoveRootNode option was redundant, it was only used together with the DragAndDrop one.
- The FollowExtractionDialogSettings was only set but never read, so we can drop it.