Collect additional testing artifacts from Appveyor.

.appveyor.yml

@@ -71,6 +71,14 @@ artifacts:
   - path: 'dist\*'
   - path: trial_test_log.txt
     name: Trial test.log
+  - path: eliot.log
+    name: Eliot test log
+
+on_failure:
+  # Artifacts are not normally uploaded when the job fails.  To get the test
+  # logs, we have to push them ourselves.
+  - ps: Push-AppveyorArtifact _trial_temp\test.log -Filename trial.log
+  - ps: Push-AppveyorArtifact eliot.log -Filename eliot.log
 
 #on_success:
 #  You can use this step to upload your artifacts to a public website.