VFS cache impl change

[alesj]

I would suggest we use LRU vfs cache by default instead of timed cache:
- http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4197635#4197635

Perhaps a max size of 10 is just fine,
as we currently already cover all the major roots
and the cache size is around 5-6.