(fix) Each test scenario should have a title so that the "Cannot find suite node" warning is not thrown

This closes #5
(fix) Travis CI build should pass now, as the version of node.js to be used is pinned to 0.10.30. 0.10.31 which is used by default seems to be buggy.
(chore) Code coverage and packages update:

* grunt-mocha-cov replaced with grunt-mocha-istanbul
* running grunt test generates code coverage reports
* Yadda upgraded
* 'local build' can be executed by running `npm test`
(chore) README informs about the status of the latest build