Allow subdomain-aware URL reversing to work when serving on non-standard port

[ezheidtmann]

This enables {% url ... subdomain='something' %} and reverse() to produce
useful results when used in runserver. Tested with runserver_plus.

[ezheidtmann]

Yay! Travis likes it!

[ezheidtmann]

Also added support for automatically determining the scheme (http/https) from the request if present in the template.

[lionleaf]

Currently running into this issue. Would be great to have this merged. Any workarounds for now? (For testing on localhost:8000 get it to return subdomain.localhost:8000/path on reverse)

[hakanw]

Very much +1 on this, if this means it solves the problems when using this app during development on localhost!

[lionleaf]

@hakanw I fixed this by adding the port to the site domain on localhost, and it now works well even with the 8000 port.

That is, in the django shell run:

>>> from django.contrib.sites.models import Site
>>> site = Site.objects.all()[SITE_ID]
>>> site.domain = 'localhost:8000'
>>> site.save()