Add cobertura/coveralls plugins (code coverage).
Enable code coverage reports for travis.
Show code coverage status in README.
Merge pull request #6 from marcjansen/code-coverage

Enable continuous code coverage reporting
Merge pull request #7 from buehner/security-test

Added a basic test for the AuthenticationProvider
Merge branch 'master' of https://github.com/terrestris/shogun2 into security-test