Latest custom field revisions

[Joel Peshkin]

In general, this looks very good.  There are a few details not yet 
addressed which I think should be ....

1) What happens when a bug is moved to a product on which the custom 
field is not relevent and then is subsequently moved to a product where 
it is?  (I suggest that the field be made invisible while in the product 
where it is not irrelevent but not lost)

2) Which name is used for the activity log?

3) What happens to the activity log on field rename?  (It should stay 
consistent)

4) In the standard templates, there will no doubt be a routine that 
handles the custom fields.  If a site customizes the templates, can they 
indicate that a field is "already done" so the routine skips a specific 
field and leaves it to template customizations?