Make sure we archive each iso properly
Fix a problem with naming the status export file for ABACUS
Fix a comment typo
Return the total audio length in the meta data

As specified in http://www.daisy.org/z3986/2005/Z3986-2005.html#Clock
Move the set-state functionality to the production namespace

This function now also sets the meta data or the produced date if the
state is set to "recorded"
Add a FIXME about an unnecessary db round trip