Imports of emulator command

PathSynopsis
cloud.google.com/go/bigtable/bttestPackage bttest contains test helpers for working with the bigtable package.
flagPackage flag implements command-line flag parsing.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
google.golang.org/grpcPackage grpc implements an RPC system called gRPC.
logPackage log implements a simple logging package.