v1.0.1

Fixed

• Database(persistent=True) kept a finished thread's connection open until close() or interpreter exit, so a long-lived Database used from short-lived threads (a recycling pool, a server, a library called from its users' threads) accumulated one open connection per thread. A thread's connection is now closed when the thread ends: the slot registry is a WeakSet and each connection has a weakref.finalize. A connection inherited across a fork is left alone, as close() already did. (#12)