http links in index

[psegs9]

The protocol part of the link to the documentation (and the two other options in that list) is hardcoded to http (no s). It's a bit irritating nowadays to have the crossed out lock to appear on a page especially if there is https available.

oscarcommerce.com/index.html

Lines 20 to 22 in 83d9628

	<li><a href="http://latest.oscarcommerce.com" class="btn btn-primary" title="Try the sandbox">Browse the sandbox</a></li>
	<li><a href="http://github.com/django-oscar/django-oscar/" class="btn btn-primary" title="View the source code">View the source code</a></li>
	<li><a href="http://docs.oscarcommerce.com/en/latest/" class="btn btn-default" title="Read the documentation">Read the documentation</a></li>

I would make a PR, but am not sure, since there are two sensible options:

• omit the protocol:

<li><a href="//latest.oscarcommerce.com" class="btn btn-primary" title="Try the sandbox">Browse the sandbox</a></li>
<li><a href="//github.com/django-oscar/django-oscar/" class="btn btn-primary" title="View the source code">View the source code</a></li>
<li><a href="//docs.oscarcommerce.com/en/latest/" class="btn btn-default" title="Read the documentation">Read the documentation</a></li>

• or add an s to the http