do all builds with unicode

.travis.yml

@@ -17,6 +17,13 @@ matrix:
           sources: &sources
             - llvm-toolchain-precise-3.8
             - ubuntu-toolchain-r-test
+    - os: linux
+      env: COMPILER=g++-5 UNICODE_OPTIONS=-DCXXOPTS_USE_UNICODE_HELP
+      addons:
+        apt:
+          packages:
+            - g++-5
+          sources: *sources
     - os: linux
       env: COMPILER=clang++-3.8 CXXFLAGS=-stdlib=libc++
       addons:
@@ -25,6 +32,14 @@ matrix:
             - clang-3.8
             - libc++-dev
           sources: *sources
+    - os: linux
+      env: COMPILER=clang++-3.8 CXXFLAGS=-stdlib=libc++ UNICODE_OPTIONS=-DCXXOPTS_USE_UNICODE_HELP
+      addons:
+        apt:
+          packages:
+            - clang-3.8
+            - libc++-dev
+          sources: *sources
 script: >
     cmake -DCXXOPTS_BUILD_TESTS=ON -DCMAKE_CXX_COMPILER=$COMPILER
     -DCMAKE_CXX_FLAGS=$CXXFLAGS $UNICODE_OPTIONS .