More custom field revisions

[Gervase Markham]

Christopher Hicks wrote:
<some very good arguments>

> One of my desired custom fields is to be able to have a server name
> field so that I could try to do all the work on a given server at the same
> time.  Having to search 12 fields for this wouldn't help much.

It seems to me that the most natural model for custom fields is this:

When you create a field, you select a number of products, between 1 and 
N, to which it applies. If you select 1, it's the same as the current 
concept of a custom field. If you select N, it's the same as the current 
concept of a global custom field. If you select any number in between, 
it's the subset.

This way, you have one mechanism for managing the fields - in a lot of 
code, they can all be treated the same rather than via this false 
dichotomy of global vs. product-specific.

The key thing is that this doesn't remove any abilities from the 
proposal - those who want only single-product and global fields can 
still have them. It also, I strongly suspect, makes the implementation 
simpler because 1-product and n-product fields have more in common 
internally.

Gerv