redirect=0 does not stop #REDIRECTs

[grimoire]

Example URL: http://manchester.openguides.org/?Locale_Great_Northern_Centre

When a user attempts to access a node which is a #REDIRECT, they are automatically redirected. The new page they are viewing tells them which page they were redirected from, and there is a link to this node with a "redirect=0" parameter. It's reasonable to assume that this link will allow you to see or edit the #REDIRECT but in fact it just redirects the user back to the target of the #REDIRECT.

[ilmari]

Changing the parameter to redirect=no makes us not need to care about definedness vs. truth.

[ilmari]

(In [1056]) Check for definedness of redirect parameter before defaulting to 1 (closes #104).