Update install SQL script

Add extra custom field columns for oc_order table.
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
Fix several typos
https://github.com/opencart/opencart/issues/1571
more api work done
https://github.com/opencart/opencart/pull/1556
Merge pull request #1562 from osworx/patch-6

Update english.php
Merge pull request #1558 from osworx/patch-4

Update header.tpl
Added missing semi-colon. Closes #1565
Updated config_ftp_host to config_ftp_hostname in admin/controller/extension/installer.php

Closes #1559
Reduced icon size on dashboard to fit when viewing on smaller window (before layout switches smaller)

Closes #1553
Added missing Amazon Checkout icon in admin area.

Closes #1545
Updated SQL file to alphabetical for recurring payment tables.

Closes #1566
Changed double to single quotes in language file.

Closes #1442
Merge pull request #1563 from Milow/typo-fixes

Fix several typos
Merge pull request #1449 from hellaslubo/patch-order-custom-columns

Update install SQL script
Added 503 header response with retry time of 60 minutes when in maintenance mode. Prevents indexing of site.
Merge branch 'master' of https://github.com/opencart/opencart