Add travis-ci configuration

.travis.yml

+language: cpp
+sudo: false
+
+cache:
+  apt: true
+  directories:
+    - /tmp/tools
+
+env:
+  global:
+    - PATH="$HOME/bin:$PATH"
+    - CMAKE_VERSION_PREFIX=3.5
+    - CMAKE_VERSION_FULL=3.5.2
+
+matrix:
+  include:
+    - env: CXX=g++-5 CC=gcc-5
+      addons:
+        apt:
+          packages:
+            - g++-5
+          sources: &sources
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-precise-3.8
+    - env: CXX=clang++-3.8 CC=clang-3.8
+      addons:
+        apt:
+          packages:
+            - clang-3.8
+          sources: *sources
+
+install:
+  - mkdir -p /tmp/tools
+  - pushd /tmp/tools
+  - if [[ ! -f "cmake-$CMAKE_VERSION_FULL-Linux-x86_64.sh" ]]; then
+      curl -SOL "https://cmake.org/files/v$CMAKE_VERSION_PREFIX/cmake-$CMAKE_VERSION_FULL-Linux-x86_64.sh";
+      chmod +x "cmake-$CMAKE_VERSION_FULL-Linux-x86_64.sh";
+    fi
+  - ./"cmake-$CMAKE_VERSION_FULL-Linux-x86_64.sh" --prefix="$HOME" --exclude-subdir --skip-license
+  - popd
+
+script:
+  - mkdir build
+  - cd build
+  - cmake .. && make

gtest @ d225acc9

-Subproject commit 0a439623f75c029912728d80cb7f1b8b48739ca4
+Subproject commit d225acc90bc3a8c420a9bcd1f033033c1ccd7fe0

test/CMakeLists.txt

 # Common variables.
-SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")
+SET (CMAKE_CXX_STANDARD 11)
+SET (CMAKE_CXX_STANDARD_REQUIRED ON)
 SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wmissing-include-dirs -Wundef -Wfloat-equal -Wshadow -Wunsafe-loop-optimizations")
-SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wdouble-promotion -Winit-self -Wvector-operation-performance -Wnoexcept -Weffc++ -Wstrict-null-sentinel")
+SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wdouble-promotion -Winit-self -Wnoexcept -Weffc++ -Wstrict-null-sentinel")
 SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Woverloaded-virtual -Wsign-promo")
 SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wvla -Winvalid-pch -Winline -Wredundant-decls")
 SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wlogical-op -Wcast-align")
 SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wcast-qual -Wpointer-arith -Wtrampolines")
 SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wold-style-cast")
-SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wzero-as-null-pointer-constant")
 SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fprofile-arcs -ftest-coverage")
 SET (CMAKE_SHARED_LINKER_FLAGS "-fprofile-arcs -ftest-coverage")