readme update: add where-to-get section
fix issue with single-step pages (closes #229)

* Fixes issue with "Done" label not shown on pages with a single
data-step.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
buttons tweaks

* Next button will not be displayed when no next step exists.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
Merge pull request #224 from sudodoki/master

readme update: add where-to-get section
Update README.md
Merge remote-tracking branch 'remotes/adrianp/inveniolabs'

Conflicts:
	intro.js
	minified/intro.min.js
	minified/introjs.min.css
Merge remote-tracking branch 'remotes/usablica-original/master'