Adjust CI config as matrix.

.travis.yml

@@ -1,10 +1,15 @@
 language: c
-os:
-  - linux
-  - osx
-sudo: required
-dist: trusty
-osx_image: xcode8.2
+
+matrix:
+  include:
+
+    - os: linux
+      sudo: required
+      dist: trusty
+
+    - os: osx
+      osx_image: xcode8.2
+
 install:
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then ./.travis/install-debian.sh; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then ./.travis/install-macos.sh; fi
@@ -12,6 +17,7 @@ script:
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then ./.travis/build-debian.sh; fi
   # the awk command is a workaround for https://github.com/travis-ci/travis-ci/issues/4704.
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then ./.travis/build-macos.sh | awk '/.{0,32}/ {print $0}'; fi
+
 deploy:
   - provider: releases
     api_key:

appveyor.yml

@@ -1,17 +1,20 @@
 version: '{build}'
 clone_depth: 1
-before_build:
+for:
+  - image: Visual Studio 2013
+    before_build:
       - git submodule update --init
       - set tag=x%APPVEYOR_REPO_TAG_NAME%
       - if %tag:~,2% == xv (set BUILD_TYPE=RelWithDebInfo) else (set BUILD_TYPE=Debug)
       - mkdir build
       - cmake -G"Visual Studio 12" -Tv120 -Bbuild -H.
-build_script:
+    build_script:
       - msbuild "build\src\solvespace.vcxproj" /verbosity:minimal /property:Configuration=%BUILD_TYPE% /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
       - msbuild "build\src\solvespace-cli.vcxproj" /verbosity:minimal /property:Configuration=%BUILD_TYPE% /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
       - msbuild "build\test\solvespace-testsuite.vcxproj" /verbosity:minimal /property:Configuration=%BUILD_TYPE% /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
-test_script:
+    test_script:
       - build\bin\%BUILD_TYPE%\solvespace-testsuite.exe
+
 artifacts:
   - path: build\bin\%BUILD_TYPE%\solvespace.exe
     name: solvespace.exe
@@ -19,6 +22,7 @@ artifacts:
     name: solvespace-cli.exe
   - path: build\bin\%BUILD_TYPE%\solvespace.pdb
     name: solvespace.pdb
+
 deploy:
   - provider: GitHub
     auth_token: