2014-09-19 blanchet 2014-09-19 reintroduced old setup for size of basic types
2014-09-19 blanchet 2014-09-19 keep obsolete interpretations in Main, to avoid merge trouble
2014-09-18 blanchet 2014-09-18 moved old 'size' generator together with 'old_datatype'
2014-09-16 blanchet 2014-09-16 tuned fact visibility
2014-09-16 blanchet 2014-09-16 register 'prod' and 'sum' as datatypes, to allow N2M through them