Sun Oct 3 08:38:46 CEST 2010

Things to fix

* Modules work fine, but what with parser macros?  Currently the way
  these are made modular is a bit of a hack.  Can this be done
  differently, or is it not a real problem?

The problem is that units and macros don't mix well.  It is possible
to define macros in terms of unit identifiers, but then these are
treated somewhat special.