Miscellaneous Improvements

- Rename 'dicts_to_saved_objects' -> 'save_objects'
- Rename dependency_ids -> relic_ids
  * They do more than process dependencies now)
- Give special meaning to pk=-1
- Always make (sure exists) a relic
- Order migrations by dependency
- Remove unnecessary try block
- Make relic_ids value assignment more explicit
  * This cryptic code was caused by trying to satisfy PEP8 in the wrong
    way. Making local variables for mutable objects is suboptimal.
- Add better error message for threadedcomment
Always make new relic, log migrations, bump south

South upgraded to fix the bug documented here:
http://stackoverflow.com/questions/20446724/django-south-error-attributeerror-datetimefield-object-has-no-attribute-mod

Cleanup save_<model> fns, always return a value
Fix threadedcomment query to be unique

This was causing a crash due to multiple objects returned.