Removed @ operator from dol_include_once

Adding @ operator to include_once makes include errors untraceable, it shouldn't be there. Errors must be thrown so that we notice them. It is PHP configuration's choice to decide wether to log them or print them.
FIX stock inconsistency when activating batch management on product which already have stock
Avoiding include in case of unexisting file
correction typo
Merge pull request #1747 from KreizIT/Fix_batch

FIX stock inconsistency when activating batch management
Trad: Update es_ES from transifex
Fix: Translation
Corrected file_exists check and little refactor
Added missing doActions for supplier order fiche.php
Refactored Dolibarr triggers:
Created a DolibarrTriggers abstract class.
Moved common variables out of construct class
Improved run_trigger method signature
Removed useless code
Fixed trigger not returning anything under some circumstances
Converted some global variables to local ones in InterfaceLogevents
Fixed little bug
Added missing $error and $errors variables
Refactored InterfaceNotification class
Corrected test
Refactor InterfaceActionsAuto
Corrected CS errors
Accidentally removed Demo trigger content