Imports of cue-ast-print command

PathSynopsis
cuelang.org/go/cue/astPackage ast declares the types used to represent syntax trees for CUE packages.
cuelang.org/go/cue/parserPackage parser implements a parser for CUE source files.
cuelang.org/go/cue/tokenPackage token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates).
flagPackage flag implements command-line flag parsing.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
go/tokenPackage token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates).
ioPackage io provides basic interfaces to I/O primitives.
osPackage os provides a platform-independent interface to operating system functionality.
reflectPackage reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types.
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.