[daisy] Daisy detachment

[tim_cranfield at goldenboat.net]

I would appreciate any feedback on what editing operations the 
detachment program should facilitate.

Some possibilities:
1)Add/edit/delete field
2)Add/edit/delete link
3)Add/edit/delete customField
4)Add/edit/delete Part
4)create Document
5)create Variant

Some questions:
-The Document interface does not have a method for adding a 
field. It just has setField(). Why is this?
-What is the difference between links and link fields?

Some considerations:
-Documents often contain images, which are other Documents. 
Should these be downloaded with the detachment?
-Things like branches and languages are stored in a Document 
object as ids. These mean a lot to a computer but not much to 
a human. It would be nice for people to see the name of the 
document owner, for example, for the document they have 
detached. Retrieving names involves connecting to the 
repository, which is not something we want to do except for 
when downloading and uploading detachments. My solution was to 
retrieve this information when the Document was first 
downloaded and store it with the Document in an implementation 
of the Document interface called DetachmentDocument. This 
implementation has fields such as ownerName for storing this 
information. Of course this information must be persisted in 
the detachment file so it can be accessed next time the file 
is opened. This means the getXml() method is no longer 
sufficient as it does not provide the name attributes I want. 
I have the schema and the generated classes for a more 
complete xml rendering, but now I'm starting to wonder if it 
is really so important for people to be able to see owner name 
or branch name since it would be much easier to stick with the 
current implementation. Otherwise, if any one has any 
suggestions or ideas they would be appreciated.