Imports of package metrics

PathSynopsis
encoding/jsonPackage json implements encoding and decoding of JSON as defined in RFC 7159.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
github.com/rcrowley/go-metricsGo port of Coda Hale's Metrics library
sortPackage sort provides primitives for sorting slices and user-defined collections.
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.
timePackage time provides functionality for measuring and displaying time.