#5 Link duplicate defects

[Stephen Holder]

Users should be able to mark one defect as being a
duplicate of another. If defect A is a duplicate of
defect B, then when viewing either A or B there
should be a quick and convenient way to navigate to
the linked defect.
This could possibly be extended to allow arbitrary
linkage between defects, with the type of link
selectable, allowing options such as "duplicate",
"related functionality", "dependency", etc. Just
duplicates would make for a good start, though.
If no one else wants to work on this, I'll try to
give it a go for the 0.7 release.