* I2NP: Various cleanup and bulletproofing

core/java/src/net/i2p/data/DataHelper.java

history.txt

router/java/src/net/i2p/data/i2np/DataMessage.java

router/java/src/net/i2p/data/i2np/DatabaseLookupMessage.java

...ava/src/net/i2p/data/i2np/DatabaseSearchReplyMessage.java

router/java/src/net/i2p/data/i2np/GarlicMessage.java

router/java/src/net/i2p/data/i2np/I2NPMessageImpl.java

router/java/src/net/i2p/router/RouterVersion.java

router/java/test/net/i2p/data/i2np/DateMessage.java