[pkg-xtuple-maintainers] latest PostBooks packages in unstable

[Daniel Pocock]

I've now completed adding the latest 4.1.0 packages to unstable,
including postbooks itself and the starter database schemas.

The postbooks-updater utility has also been accepted by the ftp-master
yesterday, so people can use the utility for upgrading existing schemas
from 4.0.2 or other versions to 4.1.0

The postbooks source package now builds a libxtuplecommon library
package.  This is to share libxtuplecommon.so with the
postbooks-updater, it is also used to share the xTuple logo (used by
desktop menus)