pODI Rev 518: SourceExtractor configuration

Added three new options to the podi_sitesetup.py:

sextractor = "/usr/bin/sex"
sex_redirect = " >& /dev/null"
sex_delete_tmps = True

This modify the execution of SourceExtractor during the WCS matching, adding compatibility with different shells and on Macs.

Note that podi_sitesetup.py is not part of the SVN system, but podi_sitesetup.py.example is. So you either have to replace the file you have or copy & paste the changes from the example file into your podi_sitesetup.py file.