Reset column configuration when database changes.  

This is necessary because the header_state blobs break between versions.

Also set up some much nicer column width defaults so it's not such a shock when a users' settings are blown away
is there a reason why you need to delete the %header_state after every update? Shouldn't it be enough in the last update?

When thinking of it. This might be better placed in `src/library/schemamanager.cpp :: upgradeToSchemaVersion`. Then we don't have to remember to place this at the end of every schema update.