Proof-reading of tutorial comments.
Merging from upstream (icons, sample).
Seems that contents id is needed.
README file corrected.
Samples corrected.
Merge remote-tracking branch 'anna/master'

Conflicts:
	tutorial-simplebox-1/simplebox/plugin.js
	tutorial-simplebox-1/simplebox/samples/simplebox.html
	tutorial-simplebox-2/simplebox/plugin.js
	tutorial-simplebox-2/simplebox/samples/simplebox.html