Added BeginnersTutorial js class.

It makes step by step tour by using bootstraptour js library.
Updated some css id in html files to make tour work correctly.
Added watch.js library to observe when css style of #editor
is changing. This is also needs to bootstraptour correct work.
Added BeginTutorial button to word picker dialog.

Added authentication before /editor action.
Also added BeginTutorial button handler in editor.js.
Reverted auth require in editors_controller#index. Updated tutorial tour.

Added the step to sign_in and checking when a user is already signed in to skip it.
Added beginners tutorial tour continuing after sign in step.
Added The End step with congratulations.
Merge branch 'develop' into feature/beginner-tutorial-tour
Reverted the_end step in beginners tutorial.

It make some problems because of Watch plugin.
Updated placement for sign-in tutorial step.
Added fix to work sign in step tutorial in Chrome.

Because dom loaded dynamically bootstraptour could not
find #synsets div after sign in step and fails.
Only in Chrome.
Merge pull request #36 from sld/feature/beginner-tutorial-tour

Feature/beginners tutorial tour