Check if we need SoilIndexPage>>readHeaderFrom:

[MarcusDenker]

SoilIndexPage>>#writeHeaderOn: (and the same im all the subclasses) is nicely factored for header writing.

But we do not have the same design for readHeaderFrom: (it is used only for the SkipList Data page).

[MarcusDenker]

It would be nice to have a symmetric readHeaderFrom: for every #writeHeaderOn:, but of course this is not really that important (it would aide understanding an simplify changes in the future, I think)