#89 Redirect link to MultiPartArticle

[Steve Pugh]

Currently, "redirect"-type links of the form

/redirect/?oid=[...]

can be used to redirect to content items. However, if
the content item is a MultiPartArticle with multiple
pages, then it is only possible to go to the first page
using this technique.

The attached patch enables "redirect" links to link
straight into any page of an MPA, using the following:

/redirect/?oid=[...]&page=3

The patch simply attaches the page parameter (if it
exists) to the redirected URL.

[Steve Pugh]

Redirect MPA patch