- Added file attribute cache and "check_dead_links" option
* Using the cache prevents waking external storage devices from standby
if links are pointing to external dirs/files (by omitting isDir/isFile),
but without such 'dead link detection' files/dirs from removed
devices will still show up in the list.
Therefore the new option "check_dead_links" has been added for
selecting the behaviour.
- raised EMCVersion