ENH: Baseline (Phase 1) workflow complete and visually inspected

ENH: Template (Atlas) workflow complete and visually inspected
ENH: Longitudinal (Phase 2) workflow complete and visually inspected

Deleted WorkupT1T2.py, WorkupT1T2AtlasNode.py (replaced by workflows/atlasNode.py), and WorkupT1T2Single.py (replaced by workflows/singleSubject.py)