Fixed hard coded path in unit test
Tuples: added FdbTuple.Equal(a, b) and FdbTuple.Equivalent(a, b) methods to fix problem with '=='

- Operator '==' between two IFdbTuple compares the references, and does not work as intended.
- The static method FdbTuple.Equals(..., ...) is similar to object.Equal(..., ...)
- FdbTuple.Equivalent(...) does the same thing, but performs a deep comparison (autocast between types)
Directory Layer: fixed a few issues with moving directories between partitions