Did my first through my first real check, added expenditure code descrip...

...tions, a model method to Committees that shows all the links that tie back to the committee (treasurers, candidates, other committees). I already restructured the Filer/Committee relationship to have the candidate be the controlling filer of all their committees, but wanted to explore some of the other links between committees so I added the model method. Also added palewire's queryset dump as a utility so I can cut out contributions that I want to look at. Added an export management command that smashes out some flat files that are easy for reporters to query. They just smush down the relationships.