Switch CI to GitHub Actions entirely

.github/workflows/deploy.yml

@@ -0,0 +1,17 @@
+name: deploy
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  deploy:
+    runs-on: ubuntu-20.04
+    steps:
+      - run: cargo install mdbook --version 0.4.6
+      - run: cd mdbook && mdbook build
+      - uses: JamesIves/[email protected]
+        with:
+          branch: gh-pages
+          folder: mdbook

.github/workflows/test.yml

@@ -0,0 +1,18 @@
+name: test
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-20.04
+    steps:
+    - uses: actions/checkout@v2
+    - run: rustup update 1.50.0 --no-self-update && rustup default 1.50.0
+    - run: cargo build
+    - name: test mdBook
+      # rustdoc doesn't build dependencies, so it needs to run after `cargo build`,
+      # but its dependency search gets confused if there are multiple copies of any
+      # dependency in target/debug/deps, so it needs to run before `cargo test` et al.
+      # clutter target/debug/deps with multiple copies of things.
+      run: for file in $(find mdbook -name '*.md'); do rustdoc --test $file  -L ./target/debug/deps; done
+    - run: cargo test