message: In .travis.yml, try using cached homebrew bottle for open-mpi.
  [skip appveyor]
diff: @@ -111,6 +111,7 @@ matrix:
  - $TRAVIS_BUILD_DIR/../hypre-2.10.0b/src/hypre/lib
  - $TRAVIS_BUILD_DIR/../hypre-2.10.0b/src/hypre/include
  - $TRAVIS_BUILD_DIR/../metis-4.0
  + - $HOME/bottles
  before_cache:
  - cd $TRAVIS_BUILD_DIR/../metis-4.0;
  mv libmetis.a ..; rm -rf *; mv ../libmetis.a .
  @@ -129,6 +130,7 @@ matrix:
  - $TRAVIS_BUILD_DIR/../hypre-2.10.0b/src/hypre/lib
  - $TRAVIS_BUILD_DIR/../hypre-2.10.0b/src/hypre/include
  - $TRAVIS_BUILD_DIR/../metis-4.0
  + - $HOME/bottles
  before_cache:
  - cd $TRAVIS_BUILD_DIR/../metis-4.0;
  mv libmetis.a ..; rm -rf *; mv ../libmetis.a .
  @@ -136,8 +138,25 @@ matrix:
  before_install:
  # No addon for brew yet, have to install OSX packages this way.
  + # - if [ $TRAVIS_OS_NAME == "osx" ] && [ $MPI == "YES" ]; then
  + # brew install open-mpi;
  + # fi
  +
  + # Use cached bottle for open-mpi:
  - if [ $TRAVIS_OS_NAME == "osx" ] && [ $MPI == "YES" ]; then
  - brew install open-mpi;
  + if [ ! -e $HOME/bottles/open-mpi.tgz ]; then
  + mkdir -p $HOME/bottles;
  + cd $HOME/bottles;
  + brew install --build-from-source --build-bottle
  + open-mpi --without-fortran;
  + brew bottle --root-url=$HOME open-mpi;
  + mv open-mpi-*.tar.gz open-mpi.tgz;
  + else
  + brew install --only-dependencies open-mpi --without-fortran;
  + cd $(brew --cellar) && tar zxf $HOME/bottles/open-mpi.tgz;
  + brew link open-mpi;
  + fi;
  + cd $TRAVIS_BUILD_DIR;
  fi
  # Update environment to find g++ 4.9 installation first.
  