I2p.i2p 2.4.0 eliminate multihomedb

This removes all references to the multihome netDb and reverses changes to HDLMJ and HDSMJ accordingly. This should close #409 (closed) by eliminating both the multihome cache and the multihome DB in favor client DB isolation. @zzz if you have time to take a look I would appreciate it but there's not much going on here that isn't subtractive.