to the XML description and handle its serialization back and
  forth between XML and S-Expr
* tests/sexpr2xmltest.c tests/xml2sexprtest.c
  tests/sexpr2xmldata/sexpr2xml-curmem.*
  tests/xml2sexprdata/xml2sexpr-curmem.*: added specific regression
  tests for this, this didn't disturb any of the other tests.
Daniel