[FIX] Directory: AddTo() needs to call ClearUrl()

If not LocalUrl will contain an old incorrect value.
[FIX] Index may not be less than 0

In some cases its -1 when moving folders or files around in the file
system and that causes an unwanted exception. This is maybe a dirty fix.
Merge pull request #567 from ToniMontana/hotfix-content-list

[FIX] Index may not be less than 0
Merge pull request #566 from ToniMontana/hotfix-directory-bug

[FIX] Directory: AddTo() needs to call ClearUrl()