add Elf_Dyn support This adds support for Elf_Dyn tags. Pull request sent to upstream: https://bitbucket.org/eliben/pyelftools/pull-request/5/add-support-for-parsing-of-the-dynamic/diff BUG=chromium-os:36453 TEST=lddtree.py works Change-Id: Iaf383eacc45adccb4dfc33e275028a8e7f58ff1e Reviewed-on: https://gerrit.chromium.org/gerrit/38667 Reviewed-by: David James <davidjames@chromium.org> Commit-Ready: Mike Frysinger <vapier@chromium.org> Tested-by: Mike Frysinger <vapier@chromium.org>