Update product.tpl

Added check for guest reviews.  Display login prompt if guest review is disabled.
Update changelog.md
Update opencart.sql

Ukrainian region names fixes.
Fix for bug since OC 1.4 with "Kharkiv Kherson" as single region.
Region codes in ISO 3166
Update common.js

Removed the clear fix in grid script and added after the ready function
Merge pull request #2038 from stalker780/patch-2

Update opencart.sql
modification update
modification update. added more vqmod features.

also added a unique code feature for uploaded xml
Merge branch 'master' of https://github.com/opencart/opencart

Conflicts:
	upload/install/opencart.sql
quick mod fix
Opencart 2.0 paypal_order field date_modified error #2036
Merge pull request #2040 from gortsilas/patch-1

Opencart 2.0 paypal_order field date_modified issue #2036
Merge pull request #2039 from latestthemes/master

Update common.js
Merge pull request #2026 from OpenCartAddons/master

Update product.tpl
Merge branch 'master' of https://github.com/opencart/opencart