- add stripe module to requirements.txt from git repo
- moved non-view methods from view to base
- added 'sponsorship' & 'date_closed' properties to opportunity model
- added 'featured' property to project model
- added create_sponsorship method to project model
- new ux treatment to opportunity panes & special treatment for sponsorships
- added modal for stripe payment subscriptions
- further layout cleanup site wide
- added client-side method to handle stripe callback