message: Update MANIFEST to avoid issues with Bazel generated files.
  Uses graft instead of global includes to get source files in the relevant directories only.
diff: include requirements.txt
  include VERSION
  include WORKSPACE
  -global-include BUILD.bazel
  -global-include *.bzl
  -global-include *.cc
  -global-include *.h
  +include BUILD.bazel
  +include tink_py_deps.bzl
  +include tink_py_deps_init.bzl
  +
  +# Collect all sources needed for build
  +graft tink
  +graft tools
  