Improve CI configuration.

This CL fixes the following issues:
* The Travis CI had the ctest invocation followed by a ";", so non-zero
  exit codes (indicating test failures) did not cause the build to fail.
* The AppVeyor CI had the ctest invocation followed by a ";", causing an
  error on Windows, where "&" plays the role of ";" [1].

The Windows CI (AppVeyor) will still be red after this CL, as some of
the tests are failing. However, this CL is a step forward, as it gets us
from failing to start tests to running tests and recording success/error
states.

[1] https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-xp/bb490954(v=technet.10)#using-multiple-commands-and-conditional-processing-symbols

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=236765633

.appveyor.yml

@@ -20,9 +20,6 @@ configuration:
   - RelWithDebInfo
   - Debug
 
-build:
-  verbosity: minimal
-
 build_script:
   - git submodule update --init --recursive
   - mkdir build
@@ -35,4 +32,4 @@ build_script:
   - cd ..
 
 test_script:
-  - cd build ; ctest --verbose ; cd ..
+  - cd build && ctest --verbose --build-config "%CONFIGURATION%" && cd ..