Set up CI with Azure Pipelines (#926)

Use Azure Pipelines for CI. This migrates away from Travis and
Appveyor.

ci/azure-test-stable.yml

@@ -0,0 +1,36 @@
+jobs:
+- job: ${{ parameters.name }}
+  displayName: ${{ parameters.displayName }}
+  strategy:
+    matrix:
+      Linux:
+        vmImage: ubuntu-16.04
+
+      ${{ if parameters.cross }}:
+        MacOS:
+          vmImage: macOS-10.13
+        Windows:
+          vmImage: vs2017-win2016
+  pool:
+    vmImage: $(vmImage)
+
+  steps:
+  - template: azure-install-rust.yml
+    parameters:
+      rust_version: stable
+
+  - ${{ each crate in parameters.crates }}:
+    - ${{ if eq(crate, 'tokio') }}:
+      - script: cargo test
+        env:
+          LOOM_MAX_DURATION: 10
+          CI: 'True'
+        displayName: cargo test
+
+    - ${{ if not(eq(crate, 'tokio')) }}:
+      - script: cargo test
+        env:
+          LOOM_MAX_DURATION: 10
+          CI: 'True'
+        displayName: cargo test -p ${{ crate }}
+        workingDirectory: $(Build.SourcesDirectory)/${{ crate }}