string Stdio.append_path(string absolute, string ... relative)
Append relative paths to an absolute path and remove any "//", "../" or "/." to produce a straightforward absolute path as a result.
"//"
"../"
"/."
"../" is ignorded in the relative paths if it makes the created path begin with something else than the absolute path (or so far created path).
Warning: This does not work on NT. (Consider paths like: k:/fnord)
combine_path()