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
// Submodules updated
Merge pull request #2021 from arnolem/patch-2

// Removing displays_errors on Profiling tool if _PS_MODE_DEV_ is disabled
[-] FO : Stores : warning thrown if hours is empty

If the "hours" field is empty and you display errors (e.g. when developing), a warning is thrown because of array_filter used on a non-array value. The generated XML gets corrupted because of this error, so the JS parser fails and no store is shown on the FO.
Merge pull request #2213 from axometeam/patch-41

[-] FO : Stores : warning thrown if hours is empty
[*] FO : Fix #PSCSX-3607, Display price correctly if specific price is set to 0
[-] BO : FixBug #PSCSX-3552 - Wrong shop address in PDF
Merge branch '1.6' of ssh://github.com/PrestaShop/PrestaShop into 1.6
[-] BO : Fix #PSCFV-11428 choose to refund voucher
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
// orderslips and refund
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
// useless statement
[-] BO : FixBug #PSCSX-3570 - Fix wrong tax calculation with free shipping
Merge branch '1.6' of ssh://github.com/PrestaShop/PrestaShop into 1.6
// follow up 7c5d1e77499604d2d9f03e140e4a405f2ad0284e
Merge branch '1.6' of github.com:PrestaShop/PrestaShop into 1.6
// little fail
[-] CORE : Fix #PSCSX-3374 handle vietnamese accent
[+] CORE: Add new hook: displayCustomerIdentityForm