Switched to bcrypt for hashing passwords

- User passwords will be rehashed with the new algorithm the next time
  they log in

JIRA: SPB-49
Merge pull request #32 from SanaMobile/49-switch-to-bcrypt-password-hash

Switched to bcrypt for hashing passwords
Setup basic page support

- Broken up index.html into header.html, nav.html, and footer.html to
  allow reusability on other django pages
- Use sites/flatpages django app for static pages (about/documentation)
  - These are exported to 'sana_builder/fixtures' folder and have to be
    imported/exported with `sana_builder/manage.py`
- Added barebone structure for Ember on `/editor` page

JIRA: SPB-50