Add after_failure in .travis.yml
Update tools/el4t
Merge branch 'travis-build-fix'

Same fix as I did for emacs-jedi here:
tkf/emacs-jedi@e6046c75cea98e1efa6bf14787fa1be90db32988

Test for emacs-snapshot failed.  But this is probably due to
a bug in emacs-snapshot.
Allow failures with emacs-snapshot