Imports of queue_leaves command

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
crypto/sha256Package sha256 implements the SHA224 and SHA256 hash algorithms as defined in FIPS 180-4.
flagPackage flag implements command-line flag parsing.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
github.com/golang/glogPackage glog implements logging analogous to the Google-internal C++ INFO/ERROR/V setup.
github.com/google/trillianPackage trillian contains the generated protobuf code for the Trillian API.
github.com/google/trillian/storage/mysqlPackage mysql provides a MySQL-based storage layer implementation.
timePackage time provides functionality for measuring and displaying time.