Update travis.

.travis.yml

@@ -1,9 +1,21 @@
 language: node_js
 node_js:
-   - "0.10" # from 2013-03 maintenance till 2016-10
-   - "0.12" # from 2015-02 maintenance till 2017-04
-   - "4"  # LTS from 2015-10  maintenance till 2018-04
-   - "5"  # devel from 2015-10 current till 2016-06
-#   - "6"  # LTS from 2016-10  maintenance till 2019-04
+  - "0.10" # from 2013-03 maintenance till 2016-10
+  - "0.12" # from 2015-02 maintenance till 2017-04
+  - "4"  # LTS   from 2015-10 maintenance till 2018-04
+  - "5"  # devel from 2015-10 current till 2016-06
+  - "6"  # LTS   from 2016-10 maintenance till 2019-04
+
+# coveralls integration
 after_success:
-   - COVERALLS_SERVICE_NAME=travis-ci COVERALLS_REPO_TOKEN=bOsNVcF2rXYY25lOxz8TqnyWCOSRqfdGD node_modules/.bin/builder test --coveralls
+  - COVERALLS_SERVICE_NAME=travis-ci COVERALLS_REPO_TOKEN=bOsNVcF2rXYY25lOxz8TqnyWCOSRqfdGD node_modules/.bin/builder test --coveralls
+
+# Fix the c++ compiler on Ubuntu 14.04
+env:
+  - CXX=g++-4.8
+addons:
+  apt:
+    sources:
+      - ubuntu-toolchain-r-test
+    packages:
+      - g++-4.8