Only show debug option if 'developer' mode checked in preferences
Remove Timezone from Report Criteria, use UserPreferences instead
Some PEP8 cleanups
Implement django forms for Report Criteria
Clean up DateTime widgets, bring back device check in report view, add debug form chooser
Add TableCriteria objects, and several example reports

- include new TableCriteria model class, and form factory
- profiler support only, for now
- added some docstrings and formatting cleanup
Clean up example QOS reports
Use criteria form to validate WidgetJob json POSTs
Save criteria initial values chosen in forms