Set up CI, add format and test scripts.

Remove unused Cargo dependencies.

test-all.sh

@@ -0,0 +1,54 @@
+#!/bin/bash
+set -euo pipefail
+
+# This is the top-level test script borrows heavily from CraneStation/wasmtime project:
+#
+# - Check code formatting.
+# - Make a debug build.
+# - Make a release build.
+# - Run unit tests for all Rust crates (including the filetests)
+# - Build API documentation.
+# - Optionally, run fuzzing.
+#
+# All tests run by this script should be passing at all times.
+
+# Repository top-level directory.
+topdir=$(dirname "$0")
+cd "$topdir"
+
+function banner {
+    echo "======  $*  ======"
+}
+
+# Run rustfmt if we have it.
+banner "Rust formatting"
+if cargo +stable fmt -- --version > /dev/null ; then
+    if ! "$topdir/format-all.sh" --check ; then
+        echo "Formatting diffs detected! Run \"cargo fmt --all\" to correct."
+        exit 1
+    fi
+else
+    echo "cargo-fmt not available; formatting not checked!"
+    echo
+    echo "If you are using rustup, rustfmt can be installed via"
+    echo "\"rustup component add --toolchain=stable rustfmt-preview\", or see"
+    echo "https://github.com/rust-lang-nursery/rustfmt for more information."
+fi
+
+# Make sure the code builds in release mode.
+banner "Rust release build"
+cargo build --release
+
+# Make sure the code builds in debug mode.
+banner "Rust debug build"
+cargo build
+
+# Run the tests. We run these in debug mode so that assertions are enabled.
+banner "Rust unit tests"
+RUST_BACKTRACE=1 cargo test
+
+# Make sure the documentation builds.
+banner "Rust documentation: $topdir/target/doc/wasi-common/index.html"
+cargo doc
+
+banner "OK"