Bugfixes

- Prévention de la suppression du dernier slot
- Correction des problèmes de \n dans la description et les commentaires
- Correction de la date de suppression du sondage
- Blindage du format de la date d'expiration du sondage

See merge request !55

	- Also fix the corresponding translation when a problem arise.

	- As it is now, description can't be in error state : we are waiting the markdown implementation to eventually change that.
	- Comments are now normaly formated (newlines are taken into account)
	- The title, description and comment regexes are now useless. Deleted.

Smartysize the date poll creation page (step 2 and 3)

* The page creation_date_poll.php is now full Smarty (step 2, step 3, error message)
* When get back from Step3, the form is filled with values stored in session

See merge request !52