Support SDMX 2.1 #29
Description
Current transformation is mostly based on SDMX 2.0. Started to add some SDMX 2.1 stuff like in commit 9151c9c ( issue #28 ) but full coverage would be nice.
See also: http://sdmx.org/wp-content/uploads/2011/04/SDMX_2-1_Major_Changes.pdf