fixed null pointer for uninitialized futures
shortcuts to ZERO
Support for changing content/domain protection, timeout refresh and
signature changes
cleanup
Fix removing and protection
Merge remote-tracking branch 'tomp2p/master'

Conflicts:
	core/src/main/java/net/tomp2p/connection/Sender.java
	core/src/main/java/net/tomp2p/futures/FutureWrappedBootstrap.java
	core/src/main/java/net/tomp2p/futures/FutureWrapper.java
	core/src/main/java/net/tomp2p/rpc/BroadcastRPC.java
	core/src/main/java/net/tomp2p/rpc/DirectDataRPC.java
	core/src/main/java/net/tomp2p/rpc/NeighborRPC.java
	core/src/main/java/net/tomp2p/rpc/PeerExchangeRPC.java
	core/src/main/java/net/tomp2p/rpc/QuitRPC.java
	core/src/main/java/net/tomp2p/rpc/StorageRPC.java
	core/src/main/java/net/tomp2p/rpc/TrackerRPC.java