UW Moodle archives plugin

The purpose of the plugin is to index directories of moodle course backups
and make the archives available for online course creation.

The configuration is an array of archive directory configs:

$CFG->local_archive_config[] =
        array('type'=>'backup1'        // storage type (backup1 = moodle 1.x backups, backup2 = moodle 2.x backups)
              'name'=>'ecow2',         // unique name
              'directory'=>'/backups'  // directory containing backups
        );


These can be included directly in config.php, or in external include files by specifying an array of filenames in
$CFG->local_archive_includes.  

For example:

$CFG->local_archive_includes = array('archive1.php', 'archive2.php);

Each included file should contain one or more assignments to $CFG->local_archive_config in the above form.

Each backup directory will be searched for moodle backups.  The individual course backups can be single-file 
standard backups, or unzipped directories.