externalized logo and landing page
externalized externalLinks
verifying branded redirects before using them
redirect landing page to externalized one if necessary
js taking external links from url via ajax
taking site header from branding or config file
portal branding refactored

 * refactored url fetching into neater functions
 * all values taken from config
 * builtin landing page decision made via null/not null variable
rename externalLinksHtml -> footerContent
logo images via https
Merge pull request #1377 from aodn/external_images_via_https

logo images via https
Hierarchical search Facets using checkboxes
tests for PortalBranding
Merge pull request #1375 from aodn/externalize_branding

Externalize branding
Hierarchical search Facets simplified labels
Merge pull request #1378 from aodn/hierarchical_checkboxOnNodes

Hierarchical search Facets using checkboxes
Load external config *after* everything else.  This means that chef can override *anything* (including log configuration, which is specifically why this change is being done).
Consistency in custom log fields (c.f. aatams) - this is to make log collection and parsing easier.
Merge pull request #1380 from aodn/external_config_last

Load external config *after* everything else.  This means that chef can ...
Fix for #1366.

This code was originally moved as a fix for #1321 but it caused #1366 so I had to move it back.
Destroying the OpenLayer Layer before we remove it from the store

This is a fix for #1321. The problem seemed to be around Tiles getting unloaded after the map on the Layer was already nulled-out. We've tried it out and it seems okay. Not 100% confident this is the right thing, though.