message: travis: move all 14.04 builds to 16.04
  This way we have a new enough cmake.
diff: @@ -4,14 +4,14 @@ matrix:
  fast_finish: true
  include:
  - os: linux
  - name: "ubuntu 14.04"
  - dist: trusty
  + name: "ubuntu 16.04"
  + dist: xenial
  compiler: gcc
  env:
  - MATRIX_EVAL="BUILD_TARGET=gcc_build"
  - os: linux
  - name: "ubuntu 14.04 - gcc 5"
  - dist: trusty
  + name: "ubuntu 16.04 - gcc 5"
  + dist: xenial
  compiler: gcc
  env:
  - MATRIX_EVAL="BUILD_TARGET=gcc_build && CC=gcc-5 && CXX=g++-5"
  @@ -23,8 +23,8 @@ matrix:
  - gcc-5
  - g++-5
  - os: linux
  - name: "ubuntu 14.04 - gcc 6"
  - dist: trusty
  + name: "ubuntu 16.04 - gcc 6"
  + dist: xenial
  sudo: false
  compiler: gcc
  env:
  