This change will ensure that the tree continues to work with go1.4.1.
All files continue to depend on golang.org/x/tools/go/types, but in a
follow-up change, I will switch the primary files to depend on the
standard go/types package. Another (smaller) set of files will be
forked and tagged, this time !1.6, due to API differences between the
two packages.
All tests pass using 1.4.1, 1.5, and ~1.6 (tip).
Change-Id: Ifd75a6330e120957d646be91693daaba1ce0e8c9
Reviewed-on: https://go-review.googlesource.com/18333
Reviewed-by: Robert Griesemer <gri@golang.org>