Cleanup core package

cmd/ipfs/daemon.go

core/bootstrap/bootstrap.go

core/bootstrap/bootstrap_test.go

core/builder.go

core/core.go

core/coreapi/coreapi.go

core/coreapi/test/api_test.go

core/mock/mock.go

core/ncore.go

core/node/builder.go

core/node/core.go

core/node/discovery.go

core/node/groups.go

core/node/helpers.go

core/node/identity.go

core/node/ipns.go

core/node/libp2p.go

core/node/provider.go

core/node/storage.go

namesys/republisher/repub_test.go