models: fix rootdir to avoid SuspiciousOperation

- must match MEDIA_ROOT in settings
Make network type configurable and fix network properties.
Add all templates
urls.py: Add forgotten file
Datasets: delete existing netfile when uploading new one.
Textwrap CD method docstrings
CD: store rtime and dtime (time started and time done).
CD: save_results stores num layers and cmtys.
CD: Add basic type and doc system for CD options
CD: options default to options when last run.
CD: Basic stats and downloading of CD results
Basic community visualization.
CD: bugfix options_dict without data
Update CDA page with visualization link.