Update Travis CI config, add AppVeyor for Windows CI coverage.

.travis.yml

@@ -1,16 +1,53 @@
-language: generic
+# Build matrix / environment variables are explained on:
+# http://about.travis-ci.org/docs/user/build-configuration/
+# This file can be validated on: http://lint.travis-ci.org/
+
+sudo: false
+dist: trusty
+language: cpp
+
+compiler:
+  - gcc
+  - clang
+os:
+  - linux
+  - osx
+
+env:
+  - BUILD_TYPE=Debug
+  - BUILD_TYPE=RelWithDebInfo
+
 matrix:
-  include:
-    - os: linux
-      dist: trusty # For Docker.
-      sudo: required # For Docker.
-      script:
-        - echo "Testing branch $TRAVIS_BRANCH of $REPOSITORY_NAME"
-        - docker run --rm -i -v $CI_SOURCE_PATH:$CI_SOURCE_PATH -e "CI_SOURCE_PATH=$CI_SOURCE_PATH" -e "HOME=$HOME" -t ubuntu:xenial sh -c "cd $CI_SOURCE_PATH; apt-get -qq update && apt-get -qq install build-essential cmake libgtest-dev; mkdir build && cd build && cmake ../ && make all && make test"
-    - os: osx
-      script:
-        - echo "Testing branch $TRAVIS_BRANCH of $REPOSITORY_NAME"
-        - mkdir build && cd build && cmake ../ && make all && make test
-before_install:
-- export CI_SOURCE_PATH=$(pwd)
-- export REPOSITORY_NAME=${PWD##*/}
+  allow_failures:
+    - compiler: clang
+      env: BUILD_TYPE=RelWithDebInfo
+
+addons:
+  apt:
+    # List of whitelisted in travis packages for ubuntu-precise can be found here:
+    #   https://github.com/travis-ci/apt-package-whitelist/blob/master/ubuntu-precise
+    # List of whitelisted in travis apt-sources:
+    #   https://github.com/travis-ci/apt-source-whitelist/blob/master/ubuntu.json
+    sources:
+    - ubuntu-toolchain-r-test
+    - llvm-toolchain-trusty-4.0
+    packages:
+    - cmake
+    - gcc-6
+    - g++-6
+    - clang-4.0
+
+install:
+# Travis doesn't have a nice way to install homebrew packages yet.
+# https://github.com/travis-ci/travis-ci/issues/5377
+- if [ "$TRAVIS_OS_NAME" == "osx" ]; then brew update; fi
+- if [ "$TRAVIS_OS_NAME" == "osx" ]; then brew install gcc@6; fi
+# /usr/bin/gcc is stuck to old versions by on both Linux and OSX.
+- if [ "$CXX" = "g++" ]; then export CXX="g++-6" CC="gcc-6"; fi
+- echo ${CC}
+- echo ${CXX}
+- ${CXX} --version
+
+script:
+- mkdir -p build && cd build && cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE &&
+      CTEST_OUTPUT_ON_FAILURE=1 make all test