added verbose error reporting (based on Iohannes Zmoelnig's patch) on console...

added verbose error reporting (based on Iohannes Zmoelnig's patch) on console from tcl side in case something is missing on startup (e.g. tkpng package).

src/t_tkcmd.c

@@ -582,6 +582,7 @@ void pdgui_doevalfile(Tcl_Interp *interp, char *s)
     if (Tcl_EvalFile(interp, buf) != TCL_OK)
     {
         char buf2[1000];
+		printf("error in file %s line %d: %s\n", buf, interp->errorLine, Tcl_GetStringResult(interp));
         sprintf(buf2, "puts [concat tcl: %s: can't open script]\n",
             buf);
         tcl_mess(buf2);