libgo: Update to current version of master library.

libgo/MERGE

libgo/Makefile.am

libgo/Makefile.in

libgo/go/archive/tar/reader.go

libgo/go/archive/tar/tar_test.go

libgo/go/archive/tar/writer.go

libgo/go/archive/zip/reader.go

libgo/go/archive/zip/writer.go

libgo/go/archive/zip/zip_test.go

libgo/go/bufio/bufio.go

libgo/go/bufio/bufio_test.go

libgo/go/bytes/buffer_test.go

libgo/go/bytes/bytes_test.go

libgo/go/bytes/reader.go

libgo/go/bytes/reader_test.go

libgo/go/compress/bzip2/bit_reader.go

libgo/go/compress/flate/inflate.go

libgo/go/container/list/list.go

libgo/go/crypto/cipher/cbc.go

libgo/go/crypto/cipher/cfb.go