First solution to provide a multi-step resolution of a Tcl interpreter in our shell wrappers. Uses some bash scripting to walk a list of candidates: 1) interp in build directory, 2) intep in install directory, 3) tcl interp in PATH. Where appropriate (cases 2 & 3), restricts search to a specific tinterp version. By relying on a generic shebang line (/bin/sh) we do not run into package-dependency restrictions on Debian. So a win-win?
- fix final refcounting bug: it was possible that classes contained in Tcl_Objs of type mixinreg were not freed, although their reference-counter became 0; now all test cases free all tcl_objs and referenced data structures allocated from nsf