copy action

The funniest things come to you just as you are falling asleep.

I was thinking how if you had a hidden select1 with an itemset with  
<copy/>, and then used a setvalue to change the value of the select1, you  
could use it to copy whole subtrees from one instance to another,

But then I realised that that just means we are missing a <copy/> action  
to go alongside <setvalue/>.

Steven