I thought I committed this last night. Ho hum. - This implements most of the rest of the new tracker config layout: - dbinit.py split between schema.py and initial_data.py - interfaces.py gone - tracker and detectors __init__.py gone - Added some missing functionality to backends: db_exists test and db_nuke. - Implemented configuration file options in postgresql backend. - Cleaned up tracker initialisation a lot.

This file contains items that need doing before the next release:

Required:
- documentation of i18n: TAL tags for translation
- translation databases in trackers
- implementing logging for roundup-server, including command-line switches
- per-property permission spec


Optionally:
- have rdbms backends look up the journal for actor if it's not set
- migrate to numeric ID values (fixes bug 817217)