Imports of lookup command

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
flagPackage flag implements command-line flag parsing.
github.com/golang/glogPackage glog implements logging analogous to the Google-internal C++ INFO/ERROR/V setup.
github.com/golang/protobuf/protoPackage proto provides functionality for handling protocol buffer messages.
github.com/google/trillianPackage trillian contains the generated protobuf code for the Trillian API.
github.com/google/trillian/examples/ct/ctmapper
github.com/google/trillian/examples/ct/ctmapper/ctmapperpb
google.golang.org/grpcPackage grpc implements an RPC system called gRPC.