[Radiant] [ANN] Page attachments extension

[Sean Cribbs]

I had mentioned this in the Radiant Core list a little while ago because 
I wanted people to test it out before I distributed it more widely, but 
I think it's time to let it loose.  Unlike the other extensions I have 
released in the last few weeks, I'm not putting this one in the Radiant 
repository, but keeping it in my own.  It may end up there later, however.

The basic idea is to create a simple way of managing 'assets' as 'page 
attachments' based on John's original comps at 
http://dev.radiantcms.org/radiant/browser/trunk/images/edit-page.png and 
http://johnwlong.com/downloads/radiant/attachments/.  The UI is not 
*exactly* the same, but I intend to fix that in the near future.  
Anyway, here's the URL for the extension:

http://seancribbs.com/svn/rails/plugins/extensions/page_attachments

Before you start using this, let me warn you about a few things.  First, 
there is very little documentation other that what I have written for 
the tags.  If you want image resizing (for the thumbnails), make sure 
you have RMagick installed.  For Win32 this obviously means the full 
package that comes with IM.  For *nix, OS/X and others, use whatever is 
necessary to get it installed, which could be a package manager, or 
could be building from source.  It can be tricky, so just be warned.

Other than installation, everything else is pretty straightforward.  
Just checkout the extension into vendor/extensions, run `rake 
db:migrate:extensions`, then start up or restart your server.  When you 
open a page for editing, cilck the 'Attachments' link toward the bottom 
to pop up the box for adding attachments.

TODO:
* Change the method of deleting attachments to not commit until page is 
saved.
* Move the 'minus' icons up to one icon in the title bar and provide a 
way to select attachment boxes with JS/CSS.

Enjoy,

Sean Cribbs