Finally got around issues with importing/reloading data in run command
Moved checking of BaseParser.populate variable to populate functions
Changed logging so that we can output to console, file or both, or none
Moved DataSet source to db folder
Updated DataSet to use sqlalchemy queries
Moved models/base.py to db/
Removed Datum import from db/models/base.py
Moved models __init__.py to db folder
Fixed a couple of bugs in DataSet class
Added manager class that inherits DataSet and sets up query etc.
Added init file to db folder
Changed reference to core to reference to db in models __init__.py
Modified Models a bit to work more with sqlalchemy

Instead of creating data member in metaclass, this is now a class
property. metaclass now deals with single table inheritance required by
derived Models, and the save function now creates a session, adds the
current model to it, then commits the changes.
Added syncdb command to commands folder
Made put missing Column calls in in base Model
Added paramsdict function to Model
Added CachedData model to handle any cached data (e.g. from resampling)
Fixed bad variable reference in CachedData.from_object
Added CachedData class to syncdb script
Added time_saved field to  Model