Merge pull request #1711 from david-wm/master

Updating PayPal Express version number needed to use Seamless Checkout (...
Changed icon on header to link to contact page. REF: #1712
Merge branch 'master' of https://github.com/opencart/opencart

Conflicts:
	upload/catalog/view/theme/default/template/common/header.tpl
Changed text string to fix within design limits.

https://opencart.atlassian.net/browse/OC-1658
more order editor work done
custom field fix for checkbox fields
more order editor work done
custom fields work finished int he order editor system
fix for eka7a mistake that actually removes all vouchers instead of just one

https://github.com/opencart/opencart/commit/0a5ba70b49af97d3cdbbc644f251f143493ea742

fix for as validation of the cart quality is complete not required!

https://github.com/opencart/opencart/commit/ac033e32f2ff8f89078f7b03b18a19d61dbc2c92

stop trying to fix stuff that is not broken!
Added missing drop table in install/opencart.sql
more order editor work done
Merge branch 'master' of https://github.com/opencart/opencart