message: Reduce cargo test parallelism.
  It looks like `cargo test` is getting SIGKILL'ed on travis and I'm not
  sure why. One possibility is that it's running out of memory. Try to fix
  this by reducing the number of jobs `cargo test` does in parallel.
diff: @@ -9,9 +9,9 @@ script:
  - cargo build --verbose
  - if [ "$TRAVIS_RUST_VERSION" = "nightly" ]; then
  cargo build --verbose --manifest-path=regex-debug/Cargo.toml;
  - RUSTFLAGS="-C target-feature=+ssse3" cargo test --verbose --features 'simd-accel pattern';
  + RUSTFLAGS="-C target-feature=+ssse3" cargo test --verbose --features 'simd-accel pattern' --jobs 2;
  else
  - travis_wait cargo test --verbose;
  + travis_wait cargo test --verbose --jobs 2;
  fi
  - ./run-shootout-test
  - cargo doc --verbose
  