Export to delimited text uses too much memory

[GoogleCodeExporter]

What steps will reproduce the problem?
1.Run a spatial analysis including PD node list
2.Export the PD node list to file
3.

What is the expected output? What do you see instead?

Huge memory use when exporting the global mammal dataset.  With the full mammal 
basedata and tree loaded, it uses about 350mb.  But on export, it used > 37Gb 
of RAM.  And, deleting the object from biodiverse doesn't free the memory.  In 
fact, on exiting biodiverse it held the memory and appeard to keep running in 
the text window.   On hard closing the text window, Biodiverse no longer 
appears in the task manager, but the 37Gb of memory still show as used.


What version of the product are you using? On what operating system?
0.18 64 bit

Please provide any additional information below.

Original issue reported on code.google.com by danielrosauer on 26 Oct 2012 at 6:59