Imports of package trustpinning

PathSynopsis
crypto/x509Package x509 implements a subset of the X.509 standard.
errorsPackage errors implements functions to manipulate errors.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
github.com/Sirupsen/logrus
github.com/docker/notary/trustmanager
github.com/docker/notary/tuf/data
github.com/docker/notary/tuf/signed
github.com/docker/notary/tuf/utils
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.
timePackage time provides functionality for measuring and displaying time.