Merge pull request #1 from opencart/master

Update code with OC updates
Merge pull request #2 from opencart/master

Merge OC current changes
Update seo_url.php

Replace "&" to "&amp;" in the query variable
Fix calc of PROFILESTARTDATE with proper "gm" func
Update changelog.md
Secure Trading fix for image.
Update README.md
https://github.com/opencart/opencart/issues/1943
Merge branch 'master' of https://github.com/opencart/opencart
https://github.com/opencart/opencart/issues/1941
https://github.com/opencart/opencart/issues/1939
https://github.com/opencart/opencart/issues/1924
Store setting placeholder image
Merge branch 'master' of git@github.com:opencart/opencart.git
Fixed load model URL Alias
Error validate updated
https://github.com/opencart/opencart/issues/1948
https://github.com/opencart/opencart/issues/1947
https://github.com/opencart/opencart/issues/1942
https://github.com/opencart/opencart/issues/1942