Better unit tests for ios/android

[springmeyer]

Recently it became clear that the ios/android builds were broken due to clang++-3.8 being installed for those platforms (and not being available). Glitches that cascade from the main .travis.yml need to be caught by unit tests somehow and this ticket will track this. Independently we could remove cascading to avoid this particularly breakage, but the issue still remains that we should be testing ios/android (and other achs?) better.