update copyright headers for 2016

README.md

doc/Doxyfile.in

include/opendht.h

include/opendht/crypto.h

include/opendht/default_types.h

include/opendht/dht.h

include/opendht/dhtrunner.h

include/opendht/infohash.h

include/opendht/rng.h

include/opendht/securedht.h

include/opendht/utils.h

include/opendht/value.h

python/opendht.pyx

python/opendht_cpp.pxd

python/setup.py.in

python/tools/benchmark.py

python/tools/dhtnetwork.py

python/tools/scanner.py

python/tools/virtual_network_builder.py

src/crypto.cpp