Copying a KDTree

[lfrfly at icqmail.com]

I would like a create a KDTree which stores ints, such that the ints 
index into a vector in the same object as the KDTree. Simple enough, 
until you consider how the object's copy constructor should be written.

It would be nice if I could copy the contents of the original KDTree 
wholesale.....but replace the lookup object with a different one 
referencing the new object's vector rather than the old one.

Maybe this is simple, maybe not, but my inability to find decent 
documentation for libkdtree++ means I'm left asking here how it could 
be done.