Permit MacOs and Windows to fail fast

.travis.yml

@@ -4,6 +4,7 @@ linux_before_install: &linuxbefore
   - sudo apt-get install -y libblas-dev liblapack-dev libatlas-base-dev gfortran
 
 jobs:
+  fast_finish: true
   include:
     - name:  "Python 3.6 on Xenial Linux"
       dist: xenial
@@ -17,6 +18,22 @@ jobs:
       dist: xenial
       before_install: *linuxbefore
       python: 3.8
+    - name: "Python 3.7.4 on macOS"
+      os: osx
+      osx_image: xcode11.2  # Python 3.7.4 running on macOS 10.14.4
+      language: shell       # 'language: python' is an error on Travis CI macOS
+      before_install:
+        - brew cask install mactex
+      allow_failures: true
+    - name: "Python 3.8.0 on Windows"
+      os: windows           # Windows 10.0.17134 N/A Build 17134
+      language: shell       # 'language: python' is an error on Travis CI Windows
+      before_install:
+        - choco install python --version 3.8.0
+        - choco install miktex.portable
+        - python -m pip install --upgrade pip
+      env: PATH=/c/Python38:/c/Python38/Scripts:$PATH
+  allow_failures:
     - name: "Python 3.7.4 on macOS"
       os: osx
       osx_image: xcode11.2  # Python 3.7.4 running on macOS 10.14.4