Merge pull request #32 from lilobase/master

Add travis-ci integration, strip_space & sanitize_string method
Add travis CI build status
Add HHVM to .travis.yml
Fix HHVM bug
Clean up PHPDoc comments
[UPDATE] add codecoverage configuration & add french word in str_to_bool (oui/non) & add an array_clean function who remove all null & false value from an array