Add rustfmt and github ci

.github/workflows/build.yml

@@ -0,0 +1,29 @@
+name: Continuous Integration Checks
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        toolchain: [ stable, beta ]
+        include:
+          - toolchain: stable
+            check-fmt: true
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v2
+      - name: Install Rust ${{ matrix.toolchain }} toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.toolchain }}
+          override: true
+          profile: minimal
+      - name: Build on Rust ${{ matrix.toolchain }}
+        run: cargo build --verbose --color always
+      - name: Check formatting
+        if: matrix.check-fmt
+        run: rustup component add rustfmt && cargo fmt --all -- --check
+      - name: Test on Rust ${{ matrix.toolchain }}
+        run: cargo test

rustfmt.toml

@@ -0,0 +1,5 @@
+hard_tabs = true # use tab characters for indentation, spaces for alignment
+use_field_init_shorthand = true
+max_width = 120
+use_small_heuristics = "Max"
+fn_args_layout = "Compressed"