Fix Django 1.10 deprecation notices

[agjohnson]

Here's all the deprecation notices we get when running against the python3.6 test suite:
https://gist.github.com/agjohnson/078be096d51dbe5921d4f81f1dae8dbe

List of applications that need attention:

• api
• bookmarks
• cdn
• comments
• donate
• gold
• notifications
• oauth
• payments
• profiles
• redirects
• restapi
• rtd_tests
• search
• settings
• static
• tastyapi
• templates
• vcs_support

More difficult issues to look at:

• doc_builder
• projects
• core
• builds

[jColeChanged]

I'm looking at core.

[jColeChanged]

I completed the warnings for py27 django 1.10 dep warnings for core. It turned out to be only spitting out warning for urls.subdomains

[ghost]

Completed for restapi
Working on redirects [no warnings]
Working on urls

[humitos]

I'm clossing this issue in favor of #3372

There are just two warnings missing but they are because third party libs.