Bug #30, Enable internationalization/ translation of SlickQuiz UI

* Adds 4 new string options, for example, 'questionCountText'
* Uses String.replace('%current', currentVar)
* https://github.com/jewlofthelotus/SlickQuiz/issues/30
* https://gist.github.com/nfreear/9979561
Bug #30, Backwards compatibility fix - internationalization/ i18n

* 'displayQuestionNumber' now works as before
* The effect can also be achieved with the new option 'questionTemplateText'
* (Amended commit.)
Bug #31, Accessibility changes via WAI-ARIA

* 'role=button' on <a href="">
* Live region and 'role=form' on container element
adding documentation around new options
Merge branch 'nfreear-master'; closes #30, closes #31