OC-1815 - Fixing mandatory fields bug when empty. Added PayPal and cheque fields to be mandatory if selected.
Fixing tabs > spaces
Merge branch 'master' of https://github.com/david-wm/opencart into OC-1815
Added FILTER_VALIDATE_EMAIL validation for email address
add the some js to auto display errors in ajax forms.
custom field fix
Merge pull request #1729 from david-wm/master

OC-1815 - Fixing mandatory fields bug when empty.
https://github.com/opencart/opencart/issues/1685
Merge branch 'master' of https://github.com/opencart/opencart
Merge branch 'master' of git@github.com:opencart/opencart.git