Remove marketing URLs from common.py

The MKTG_URLS dictionary is overwritten completely in aws.py anyway, and we
shouldn't be trying to keep both the production config and LMS code in sync
with changes to the marketing site.

Fix links to honor code, ToS, and privacy policy for marketing site

Fix registration button text

Fix courses link in LMS header when not logged in

be more forgiving about the iframe url

If anything after mktg/ does not parse as a course-id return "coming soon"
This will prevent 404 errors when urls are incorrect on the marketing
site.

Make register button for marketing site break out of iframe

Better error handling for when marketing urls are missing

Redirect from LMS courses page to marketing courses page

(Only if marketing site is enabled)

Use window.top.location.href instead of location.href for redirection.

edx.org - resolved iframe button styles in IE + added in coming soon state

edx.org - resolved (in a dirty way) iframed buttons picking up style in IE and added in coming soon style treatment

Fix links between marketing site and courseware.

* Fix indentation/line break issues
* Handle marketing root URL as a separate case in marketing_link
* Move link map to its own setting.

Update course registration flow for non-modal registration and login

Jarv/drupal new/iframe

Pep8 fixes

and use it for the new marketing site links.

access login_required page.