message: Try to force travis to use modern tools
diff: dist: trusty
  sudo: required
  -language:
  - - cpp
  -compiler:
  - - gcc
  +matrix:
  + include:
  + - compiler: gcc
  addons:
  apt:
  sources:
  - ubuntu-toolchain-r-test
  packages:
  - - gcc-6
  - - g++-6
  - - cmake
  + - g++-4.9
  + env: COMPILER=g++-4.9
  + - compiler: gcc
  + addons:
  + apt:
  + sources:
  + - ubuntu-toolchain-r-test
  + packages:
  + - g++-5
  + env: COMPILER=g++-5
  + - compiler: clang
  + addons:
  + apt:
  + sources:
  + - ubuntu-toolchain-r-test
  + - llvm-toolchain-precise-3.6
  + packages:
  + - clang-3.6
  + env: COMPILER=clang++-3.6
  + - compiler: clang
  + addons:
  + apt:
  + sources:
  + - ubuntu-toolchain-r-test
  + - llvm-toolchain-precise-3.7
  + packages:
  + - clang-3.7
  + env: COMPILER=clang++-3.7
  +
  +before_install:
  + - sudo apt-get update -qq
  + - sudo apt-get install -y libopencv-dev
  script:
  # Link gcc-6 and g++-6 to their standard commands
  - ln -s /usr/bin/gcc-6 /usr/local/bin/gcc
  