Imports of cue-ast command

PathSynopsis
cuelang.org/go/cue/astPackage ast declares the types used to represent syntax trees for CUE packages.
cuelang.org/go/cue/ast/astutil
cuelang.org/go/cue/errorsPackage errors defines shared types for handling CUE errors.
cuelang.org/go/cue/formatPackage format implements standard formatting of CUE configurations.
cuelang.org/go/cue/loadPackage load loads CUE instances.
cuelang.org/go/internal/astinternal
flagPackage flag implements command-line flag parsing.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
logPackage log implements a simple logging package.
osPackage os provides a platform-independent interface to operating system functionality.
slicesPackage slices defines various functions useful with slices of any type.