Updated a few different bug fixes and performance tweaks
Merge pull request #8 from sjyk/join_rawsc

Updated a few different bug fixes and performance tweaks
Renamed amt_server to crowd_server.
Added a base app with generic models/views for interacting with a crowd.
Refactored AMT models to use the base model.
Fixes to views and storage so that AMT now runs on the basecrowd abstraction.
Updating celery tasks for basecrowd model.
Added better start/stop scripts for the crowd server.
Bugfix in new celery task.
Cleaner class for registering crowds and auto-appending related fields.
Added a basic interface for new crowds.
Storage functions make saving optional.
Updated create_hits view to use generic interface.
Made crowd urls more generic, moved generic view code to basecrowd.
Made stop script only kill python processes started in crowd_server.
Integrated model and interface registration, Implemented the generic view to delete tasks.
Better error handling in disable_hit AMT API call.
Moved site fixture to basecrowd app.
Implemented generic view for getting task assignment interfaces.
purging HIT references from generic views.