merge nat
Merge remote-tracking branch 'tomp2p/master'

Conflicts:
	core/src/main/java/net/tomp2p/peers/PeerMap.java
	nat/src/main/java/net/tomp2p/relay/RelayBuilder.java
	nat/src/main/java/net/tomp2p/relay/RelayConnectionFuture.java
	nat/src/main/java/net/tomp2p/relay/RelayManager.java
	nat/src/test/java/net/tomp2p/relay/TestRelay.java