Merge branch 'development' of https://github.com/PrestaShop/PrestaShop into bootstrap

Conflicts:
	admin-dev/themes/default/css/modules.css
	admin-dev/themes/default/template/controllers/carts/helpers/view/view.tpl
	admin-dev/themes/default/template/controllers/groups/helpers/form/form.tpl
	admin-dev/themes/default/template/controllers/groups/helpers/view/view.tpl
	admin-dev/themes/default/template/controllers/products/helpers/form/form.tpl
	admin-dev/themes/default/template/controllers/products/images.tpl
	admin-dev/themes/default/template/controllers/products/prices.tpl
	admin-dev/themes/default/template/helpers/form/form.tpl
	admin-dev/themes/default/template/helpers/list/list_header.tpl
	classes/Autoload.php
	classes/Carrier.php
	classes/Product.php
	classes/ProductSale.php
	classes/Tools.php
	classes/Validate.php
	classes/tax/TaxRulesTaxManager.php
	controllers/admin/AdminPPreferencesController.php
	controllers/admin/AdminPerformanceController.php
	install-dev/install_version.php
	js/admin_carrier_wizard.js
	modules/blockcategories/blockcategories.php
	modules/blocklayered/blocklayered.php
	modules/statsequipment/statsequipment.php
	modules/statsproduct/statsproduct.php
	modules/watermark/watermark.php
	themes/default/address.tpl
	themes/default/authentication.tpl
	themes/default/category.tpl
	themes/default/contact-form.tpl
	themes/default/css/history.css
	themes/default/header.tpl
	themes/default/js/cart-summary.js
	themes/default/js/product.js
	themes/default/mobile/order-detail.tpl
	themes/default/modules/blocksearch/blocksearch.tpl
	themes/default/modules/productcomments/productcomments.tpl
	themes/default/order-carrier.tpl
	themes/default/order-detail.tpl
	themes/default/order-opc-new-account.tpl
	themes/default/product.tpl

classes/db/Db.php

@@ -523,13 +523,13 @@ abstract class DbCore
 			$this->last_cached = true;
 			return $result;
 		}
-
 		$this->result = $this->query($sql);
 		if (!$this->result)
 			return false;
-
 		$this->last_cached = false;
 		$result = $this->nextRow($this->result);
+		if (is_null($result))
+			$result = false;
 		if ($use_cache && $this->is_cache_enabled)
 			Cache::getInstance()->setQuery($sql, $result);
 		return $result;