[PATCH] complete the StoreEntry and StoreIOState constructors

Hi all,
  StoreEntry and StoreIOState's constructors don't initialize all
their data members; the layering is currently not very robust and
initialization relies on the caller.
This patch attempts to fill in all data members for those classes for
which I could find a reasonable default; I'm not committing right away
as I'd like someone with more expertise than me to review that the
values I've chosen make sense.

Thanks

--
    /kinkie