[PATCH] Reinstate Mempools useage for MemBlob

Hi all,
   this is the second snippet of the MemPools integration patch for
MemBlob. It depends on the "Enable string mempools to work correctly
during initialization phase" patch I sent earlier on.

Commit summary:
Ensure that MemBlobs use MemPools manage memory areas, and remove
duplication of code with MemPools.

Thanks

-- 
    /kinkie