Provide Tcl9 compatibility after TIP #673TIP #673 removed "trace variable", which was deprecated since therelease of Tcl 8.4. However, since Tcl does not warn aboutdeprecations, so it was not detected until TIP #673 removed thecommand for Tcl9.
nsf.c: - change name of enumeratorConverterEntry to Nsf_EnumeratorConverterEntry, move it with NSF_ARG_* flags to tcl.h to make it available in derived modules using the converter - Added editor hints for a more uniform appearance
- created own directory structure xotcl under library containing doc, tests, apps, lib etc. and moved obvious content here. - adjusted regression test and old documentation system to work with new structure