Unpickling TableBundle fails due to __getattr__() implementation

[jfcorbett]

According to docs, unpickling may call __getattr__(), and __init__() is not necessarily called.

This causes an infinite recursion when unpickling TableBundle: __getattr__() calls unique(), which asks for self._tables_named, which calls __getattr__("_tables_named") presumably because self._tables_named was never initialized in __init__().

Unfortunately this means that TableBundle cannot be pickled!