Restore old behaviour

A thing that bothered me for quiete a while now: When I filter away
unchanged entries in the WT, all directories are still shown.

This is regression was introduced with the moving to the proxy model for
filtering. The actual cause is that we don't recursively check if the
filter rules apply to all children. But this was hidden by a
"workaround" bugfix (DirItems didn't report status, so they were just
always accepted).

This commit fixes both issues and restores the behaviour before the
change to the filter proxy...
Merge pull request #85 from macgitver/sc/b/fix_wt

Working Tree: Restore filter behavior from before using ProxyFilters