Delete Travis/AppVeyor configurations (#266)

Now that this repo has migrated to Azure Pipelines they shouldn't be
necessary any more!

.travis.yml

@@ -1,41 +0,0 @@
-# Travis CI script. See https://travis-ci.org/ for more info.
-
-os:
-    - linux
-    - osx
-language: rust
-rust:
-    - 1.36.0
-    - beta
-    - nightly
-matrix:
-    allow_failures:
-        # We try to be compatible with beta and nightly, but they occasionally
-        # fail, so we don't allow them to hold up people using stable.
-        - rust: beta
-        - rust: nightly
-    # Similarly, we don't need to hold up people using stable while we wait
-    # for the results which may fail.
-    fast_finish: true
-dist: xenial
-sudo: false
-before_script:
-    # If an old version of rustfmt from cargo is already installed, uninstall
-    # it, since it can prevent the installation of the new version from rustup.
-    - cargo uninstall rustfmt || true
-    - cargo install --list
-    # If we're testing beta or nightly, we still need to install the stable
-    # toolchain so that we can run the stable version of rustfmt.
-    - rustup toolchain install stable
-    # Install the stable version of rustfmt.
-    - rustup component add --toolchain=stable rustfmt-preview
-    - rustup component list --toolchain=stable
-    - rustup show
-    - rustfmt +stable --version || echo fail
-    # Sometimes the component isn't actually ready after being installed, and
-    # rustup update makes it ready.
-    - rustup update
-    - rustfmt +stable --version
-script: ./test-all.sh
-cache:
-    cargo: true

appveyor.yml

@@ -1,15 +0,0 @@
-os: Visual Studio 2017
-environment:
-  matrix:
-  - TARGET: x86_64-pc-windows-msvc
-install:
-  - appveyor DownloadFile https://win.rustup.rs/ -FileName rustup-init.exe
-  - rustup-init.exe -yv --default-host %target%
-  - set PATH=%PATH%;%USERPROFILE%\.cargo\bin
-  - rustc -vV
-  - cargo -vV
-  - git submodule update --init --recursive
-build: false
-test_script:
-  - set RUST_BACKTRACE=1
-  - cargo test --verbose --all