[pca] hiding SOA data from "ps"

[Martin Paul]

Martin Paul wrote:
> I see that there is a File::Temp module for the very purpose of creating 
> safe tmp files in perl >= 5.6.1, so I'll probably switch to that for all 
> the temporary files/dirs I use.

Done. The current development release of pca includes:

    * Safe creation of temporary files/dirs to avoid race condition

Martin.