api/go1.6.txt: add debug.SetTraceback, build.Package.InvalidGoFiles

Change-Id: Ib00e866e29681631f6fa3a14e7d81c25fc3c8500
Reviewed-on: https://go-review.googlesource.com/18052Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

api/go1.6.txt

@@ -180,6 +180,7 @@ pkg encoding/asn1, const TagUTF8String = 12
 pkg encoding/asn1, const TagUTF8String ideal-int
 pkg go/build, const AllowVendor = 8
 pkg go/build, const AllowVendor ImportMode
+pkg go/build, type Package struct, InvalidGoFiles []string
 pkg go/constant, func ToComplex(Value) Value
 pkg go/constant, func ToFloat(Value) Value
 pkg go/constant, func ToInt(Value) Value
@@ -254,6 +255,7 @@ pkg net/url, method (InvalidHostError) Error() string
 pkg net/url, type InvalidHostError string
 pkg os/exec, type ExitError struct, Stderr []uint8
 pkg regexp, method (*Regexp) Copy() *Regexp
+pkg runtime/debug, func SetTraceback(string)
 pkg strconv, func AppendQuoteRuneToGraphic([]uint8, int32) []uint8
 pkg strconv, func AppendQuoteToGraphic([]uint8, string) []uint8
 pkg strconv, func IsGraphic(int32) bool