use msgpack for dht protocol and value serialization

configure.ac

include/opendht/crypto.h

include/opendht/default_types.h

include/opendht/dht.h

include/opendht/dhtrunner.h

include/opendht/infohash.h

include/opendht/serialize.h

include/opendht/value.h

src/Makefile.am

src/crypto.cpp

src/default_types.cpp

src/dht.cpp

src/dhtrunner.cpp

src/securedht.cpp

src/value.cpp