change the key name "field-errors" to "field_errors".

as "-" is not allowed as a part of key name in javascript

Would be nice to keep the custom subdomain, but too much of a PITA
right now.

Modified alazaro's commit sot that both markdown < 2.1 and >= 2.1 are
supported

The test checks if either matches the old or the new style.

ADMIN_MEDIA_PREFIX no longer supported in django1.4

This will run the linkcheck and build the html docs, turning any warnings into
errors.
Also changed the theme to sphinx-doc and added version to be displayed in the
docs.

Removed unused code. No longer needed with  markdown 2.1.0.

Use 1.4's CSRFMiddleware, so that PUT and DELETE get CSRF validation if session authentication is being used