Revision 3330

Major updates to the file manager to allow it to:

1.  Show dates and sizes of files (optionally, since some browsers
    don't handle the CSS to change to a monospaced font).

2.  Provide better control over renaming of uploaded files whose
    names already exist (there is a checkbox for overwriting them
    automatically; if unchecked, the user is prompted for a new name).

3.  Allow the creation or gzipped tar archives from files in the
    course directory.  Multiple files and directories can be selected
    to be included in the archive.  If only one file is selected, the
    archive will have it's name with ".tgz" appended; if mulitple
    files are selected, the archive will get a unique name starting
    with the course ID.

4.  Provide a checkbox that controls whether uploaded .tgz archives
    are unpacked automatically, and a second that controls whether the
    unpacked archive file is deleted afterward.  Files from the
    archive will be unpacked into the current directory, and will
    overwrite existing files silently.

5.  Follow symbolic links that are to files or directories within the
    course hierarchy.  In addition, there is a new variable in
    global.conf that provides a list of "valid links"; these are
    directories to which the FileManager is allowed to follow symbolic
    links.  The system administator can add directories to this list
    in order to allow professors to access limited areas outside their
    course directory (but they still need to have a symblic link
    within their course to those areas in order to view them).

I think this covers all the current FileManager requests, and this
closes bug#791.