settings/base.py: adding additional plugins to ckeditor and updating …

[philli-m]

…unload filename so doesn't clash with plugins

• The preview is broken after save but the iframe remains so it's 'working' this might be a long standing problem though according to some issues I found
• It also has the capability added to all ckeditors for testing purposes but I think we only want it on the collapsible element one but until we are happy with whats happening it's good to have the tester options.
• The nocookie URL from youtube may or may not solve our problem, I didn't find much on how to add the alert though?!
• And apparently travis is failing?! I have only just notice that

[fuzzylogic2000]

Cool! But when I fix travis (by also chaning unload_warning to warning_unload in webpack), I get the target not defined and not-stopping loading again. :( Don't know what to do about that! Or maybe, we don't use the warning_unload on the dashboard form pages with ck editor?

[fuzzylogic2000]

Right, but we don't use different templates for the different dashboard forms. :(

[fuzzylogic2000]

I just updated the ck editor. So before we go on, let's rebase! :)

[fuzzylogic2000]

Very nice! It works!