- nsf.c:
- Let "/cls/ info mixinof -closure" return as well implicit mixin classes
  to make it easier to determine class dependencies.

  Example:

     nx::Class create M0
     nx::Class create M1 -superclass M0
     nx::Class create M2 -superclass M1

     nx::Class create C
     nx::Class create D -superclass C

     C mixin add M2

     # M2 is mixed into C, and implicitely into D
     #
     # Since M2 is a subclass of M1, classes C and D depend as well
     # on M1 and M0, as seen in the heritage:

     ? {C info heritage} ":M2 ::M1 ::M0 ::nx::Object"
     ? {D info heritage} ":M2 ::M1 ::M0 ::C ::nx::Object"

     # previously, only "M2 info mixinof -closure" showed the
     # mixin relations, even with "-closure", while M1 and M0 did not.

     ? {M2 info mixinof -closure} "::C ::D"

     # now these show the same relations (in this example).

     ? {M1 info mixinof -closure} "::C ::D"
     ? {M0 info mixinof -closure} "::C ::D"
nx.tcl:
- removed
    /cls/ info configure parameters
    /cls/ info configure
    /cls/ info syntax
  Use e.g. "/cls/ info lookup parameters create" instead
- ignore generated .txt files
- add test file nsf-cmd.test
- adapt mixinof.test to the additional information
- transform mixinof.test to newer style regression test with autoated object deletion
- update of TODO and regression test
- improve spelling
- minor cleanup