Improve manually added links UI with JS

While this patch has made it easier for non-coders to add related links, IMO, this can be improved.

A few criteria/considerations:

• There ought to be separate inputs for each field - URL, title (perhaps description) etc.
• The user shouldn't have to refresh the page to add a new link [or in other words a new set of input fields].
• Link order (weighting) and removal of added links should be addressed, again, without a page refresh.
• Users with JS disabled should be able to use the textarea we have currently, i.e. graceful degradation.

IMO, the relatedlinks fieldset in the node form could look something like this:

1. google      [down]    [delete]
2. yahoo  [up] [down]    [delete]
3. drupal [up]           [delete]

Add link: [URL input] [title input] [add link]

JS could perhaps *hide* the currently used textarea for manual links and replace it with the above UI (in a float). Clicking the [add link] will essentially populate the existing textarea (which is not visible to the user).

The [up] and [down] buttons control weight, while the delete button removes a link. This will also accomplish the weight issue without the need of an extra weight field.

Hope that made sense. Your thoughts on this are appreciated. And patches are very welcome!

Cheers,
-K