Start laying out the new data model.
Merge branch 'sprint-3' into celery
Add new objects to data model. Integrate the changes that Brian made
in the specification.
ISSUE#83

Update data model to use the new integrated data model that Brian and I
have been working on. Break the loader into different tasks using Celery.
Test loading of files in Celery.

This is an initial checkin with some small amount of testing.
ISSUE#83

Create two different task calls: One to load a single directory (and sub directories)
and another to load a list of directories (and their respective sub directories).

Wrap calls in exception handling to resubmit on failure.
ISSUE#83
As a part of breaking up the tasks for creating the data model I moved
database and table creation to a command.
Formatting.
ISSUE#83

Fix up database creation and add in new tables/delete old tables.
ISSUE#83

Add new model elements for conditions and params. Move some params to
conditions to further describe the object. Rework the layout to move
basic functionality into DataItem.
ISSUE#83

Rework DataItem into a base class used by DataFile and DataParam (and
soon to be used by DataSet).
Rework inheritance.
ISSUE#83
Fixup task to work with changed data model
Merge branch 'sprint-3' into celery
ISSUE#83
Use common terminology: params --> conditions
ISSUE#83
Inherit from DataItem
ISSUE#83
Place holder for code to perform indexing.
ISSUE#83
Refactor metadata loader to use send jobs to a celery task. Simplified
metaloader (and thus updated loaddata.sh script) to always go to localhost.
ISSUE#83

Fix up capitalization error when I converted functions and variables
to lowercase.

Make threadsafe rethinkdb calls (because I'm using a global connection)
by moving the call into the task. Need to investigate thread safety further.
ISSUE#83
Add copying and removing data.
ISSUE#83

Usergroup id is the same as the name.