[PATCH] shared dpointer for duchain

[David Nolden]

I cannot believe how big the impact of this change on memory-usage. Now with 
whole kdevelop-4 parsed, kdev4 now takes only about 304 MB of virtual memory. 
I think it was more than 600 to 700 MB after my big patch to the environment 
manager.

Now we've reduced the memory-usage from more than 1,5 GB to 300MB, I'd call 
that a success. :)

greetings, David