wip with DHT

@whyrusleeping @jbenet this is a WIP with the DHT.

wip

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

Conflicts:
	epictest/addcat_test.go
	exchange/bitswap/testnet/peernet.go
	exchange/bitswap/testutils.go
	routing/mock/centralized_server.go
	routing/mock/centralized_test.go
	routing/mock/interface.go