Improve tests

* Comment existing failling test (will be corrected on next commit)
* Add unit tests (failling because of a bug on insertSpans method)
* Improve Grunt tasks to manage all that
Correct nearly all bugs on insertSpans and expose it so people can use it when overriding asHtml
Remove @private since I want to expose it to the universe
Remove FIXME and add console.error if that happen again
Merge pull request #57 from pauldijou/fix-spans-rendering

Fix spans rendering