Remove Travis as CI test

.travis.yml

@@ -1,73 +0,0 @@
-language: rust
-rust:
-  - 1.40.0
-  - stable
-  - beta
-  - nightly
-
-# Need to cache the whole `.cargo` directory to keep .crates.toml for
-# cargo-update to work
-cache:
-  directories:
-    - /home/travis/.cargo
-
-# But don't cache the cargo registry
-before_cache:
-  - rm -rf /home/travis/.cargo/registry
-
-matrix:
-  # Performance tweak
-  fast_finish: true
-  # Ignore failures in nightly, not ideal, but necessary
-  allow_failures:
-  - rust: nightly
-
-  # Only run the formatting check for stable
-  include:
-  - name: 'Rust: format check'
-    rust: stable
-    install:
-    - rustup component add rustfmt
-    script:
-    - cargo fmt --verbose --all -- --check
-
-addons:
-  apt:
-    packages:
-      - gcc-arm-linux-gnueabihf
-      - libc6-dev-armhf-cross
-      - libpulse-dev
-      - portaudio19-dev
-      - libasound2-dev
-      - libsdl2-dev
-      - gstreamer1.0-dev
-      - libgstreamer-plugins-base1.0-dev
-
-before_script:
-    - mkdir -p ~/.cargo
-    - echo '[target.armv7-unknown-linux-gnueabihf]' > ~/.cargo/config
-    - echo 'linker = "arm-linux-gnueabihf-gcc"' >> ~/.cargo/config
-    - rustup target add armv7-unknown-linux-gnueabihf
-
-script:
-    - cargo build --locked --no-default-features
-    - cargo build --locked --examples
-    - cargo build --locked --no-default-features --features "with-tremor"
-    - cargo build --locked --no-default-features --features "with-vorbis"
-    - cargo build --locked --no-default-features --features "alsa-backend"
-    - cargo build --locked --no-default-features --features "portaudio-backend"
-    - cargo build --locked --no-default-features --features "pulseaudio-backend"
-    - cargo build --locked --no-default-features --features "jackaudio-backend"
-    - cargo build --locked --no-default-features --features "rodio-backend"
-    - cargo build --locked --no-default-features --features "sdl-backend"
-    - cargo build --locked --no-default-features --features "gstreamer-backend"
-    - cargo build --locked --no-default-features --target armv7-unknown-linux-gnueabihf
-
-notifications:
-  email: false
-  webhooks:
-    urls:
-      - https://webhooks.gitter.im/e/780b178b15811059752e
-    on_success: change  # options: [always|never|change] default: always
-    on_failure: always  # options: [always|never|change] default: always
-    on_start: never     # options: [always|never|change] default: always