Removing displays_errors on Profiling tool if _PS_MODE_DEV_ is disabled

 - Profiling displays errors only if _PS_MODE_DEV_ is enabled (Previously, it override error managment)
 - Removing obsolete functions
"Cannot redeclare class XXXCore"

"Cannot redeclare class XXXCore"
This error sometimes appear when we pay by check or transfer.

Adding some require_once here instead of require solve the error for me.
// restore escape '
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
// fix file upload
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
[*] Installer : Add new 'reduction_tax' field in specific_price table
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
// remove notice when create a new product
// follow up a7aff50baa9269f0ef6aedd438d9a4f0df63b93d
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
Update Attribute.php

Update everything within one SQL Statement. Improved Performance
[+] BO : Allow catalog rules to be set tax excl. or tax incl. (see #PSCSX-3180 and 348433bbfd1dff9839d74fb87e571b4b525ab39e)
[-] [FO] Manufacturer and Supplier meta description

HTML tags in manufacturer and supplier meta description are never stripped
[-] FO: Product::getNewProducts() perfs improvements
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
// follow up 99da8748eb4fae94ef204ed7526a2a19945de2d0
[*] BO: Log the connections to the BackOffice
// follow up https://github.com/PrestaShop/PrestaShop/pull/2198
Merge pull request #2201 from Comkwatt/patch-2

[-] CORE : "Cannot redeclare class XXXCore"