handle user delay between subscription and registration (#58):
- delete unconverted user credit (triggers a new attempt)
- ask new registrants to refresh page after 5 mins
project tidying:
- update project links (source.puri.sm)
- update copyright bylines (just "Purism SPC")
- update README
- switch to pipfile-based dependencies and minimally update dependencies according to pipenv reports
- update references to requirements.txt (still used for regular installs)
Signed-off-by: David Seaward david.seaward@puri.sm