FILEIO: make path strings const.
FILEIO: add common path string manipulation routines.
FILEIO: convert go_updir to use new path manipulation routines.
FILEIO: convert open_config to use new path manipulation routines.
FILEIO: remove change_dirs.
PJ: clean up init_inks.

The wildlist is no longer used since the optional test inks were made
static in commit 3d5eb93235801900edbb324a7beb895902ec50e4.