XSB Src (SVN)-old

This file somehow got corrupted -- removed.

added:
has_library_dir/1
remove_lib_dir/1
removeall_lib_dir/1
These are now needed for the user to facilitate checks because of file standardization.
Also added push(...) to add_library_dir. This is like a(...) but doesn't retract the directory -- onyly asserts-a.

added remove_lib_dir/1

backed out the standardization change to load_dunc/2, which was incorrect.
The other standardization changes stay.

remove xwams before running the tests so that the tests would be clean.

Added path_sysop standardize (to resolve symlinks & expand) and readlink (to resolve 1 syslink).
Change consult/loader to use API to manipulate consult_file_loaded and load_dyn_file_loaded. That API always standardizes filenames before doing anything. Load and add_lib_dir also standardize files.

no longer tries to remove test_ec.xwam, which led to a spurious warning.

got rid of possible memory leak in file_readlink

added the forgotten return statement in the windows branch

file standardization now first expands the file name and only then replaces symlinks with the real thing.