Update install SQL script

Add extra custom field columns for oc_order table.
more api work done
more api work done
Changed hard-coded language string. Closes #1538
Merge branch 'master' of https://github.com/opencart/opencart
https://github.com/opencart/opencart/issues/1547
Merge branch 'master' of https://github.com/opencart/opencart
more api work done
https://github.com/opencart/opencart/issues/1546
https://github.com/opencart/opencart/issues/1544
https://github.com/opencart/opencart/issues/1542
more api work done
https://github.com/opencart/opencart/issues/1543
reverted the serialize back as testing code using json was left over
https://github.com/opencart/opencart/issues/1548
https://github.com/opencart/opencart/issues/1549
more api work done
Added Meta Tag Keyword on Homepage
Added nl2br opening times on contact page
Update header.tpl

+ titles to header icons
- last empty line
Update english.php

1 ``tab_profile`` too much