Fix the clean all button in the Fototoon activity

[llaske]

The clean all button in the Fototoon activity toolbar is supposed to remove all content.

Currently, it does nothing.
The objective of this issue is:

• Fix the non working clean all button
• Add a confirmation box before effectively cleaning all the content

The confirmation box should look like a standard confirmation box in Sugarizer (don't use the standard browser dialog box). Text of the dialog box should be localized.

[sarthak-g]

Clean all button is working properly. See:

I think only confirmation box has to be added.

[llaske]

Hmmm, look like it works when the activity is reopened from the datastore but not when it was just created. See below:

[sarthak-g]

You want "clean all" button should bring "3 of 3" (as in above) to "1 of 1" ?

[llaske]

Yes it should be "1 of 1" because the only remaining page should be the first one with title.

[llaske]

Fixed in #554