added cleanup of orphan photos after photo save
Removed possibly overly aggressive photo model cleaner.
Added organization model for source and steward. Trails index page works, not much else.
Fix trail photo issue with new steward/source relations.
Added trailhead organization relation, returning source/steward correctly in json.
Organization refactor for trailhead index/show/edit
Organization refactoring for segment source/steward.
Consolidated migrations into original models; added per-segment use fields