Add tensorflow to .travis.yml
Add tensorflow to .travis.yml

Done it without sudo so this may not work yet.

Signed-off-by: Jamie Townsend <712d3bf917252432b8abdc41edb77e32fa2cc414@gmail.com>

j-towns/pymanopt,pymanopt/pymanopt,nkoep/pymanopt,tingelst/pymanopt,nkoep/pymanopt,pymanopt/pymanopt,nkoep/pymanopt