Test that Togglz is working

[php-coder]

In commit 69214f4 I've fixed Togglz that didn't work. To avoid such breakage we need a test for this case.

I suggest to add a special feature that is always disabled. On the main page we will show a (non-localized) message if the feature is active. Our test will check that this message isn't shown.

[php-coder]

On the main page we will show a (non-localized) message if this feature is active

I suggest to show a smile instead. Let's append it to the footer. At this moment looks like

Slava Semushin, 2009-2019

but when this feature is enabled it should show the smile, like this:

Slava Semushin, 2009-2019 :-/

[php-coder]

The idea behind using a smile and adding it to the main page is that if this goes to production somehow, it could be easier spotted by me and it won't show something inappropriate to the users at the same time.