* zip.h removed old test symbols
* path_util fixed bug in mixed-separating-slash handling
* renamed ERR_OK to INFO_OK; allows searching for "return ERR_" to yield
all actual errors (instead of having to filter out ERR_OK)
This was SVN commit r3945.
also remove some stupid "returns ERR_OK or negative error code"
comments, which is now guaranteed by LibError return type anyway.
This was SVN commit r3807.