Add coveralls (coverage web service) #1264
prevent install error nokogiri on Ruby < 1.9.2

<pre>
Gem::InstallError: nokogiri requires Ruby version >= 1.9.2.
An error occurred while installing nokogiri (1.6.0), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.6.0'` succeeds before bundling.
</pre>
Use CHILIPROJECT_LANG environment var to set lang in default data loader