Multiple Campaigns

Refactored to support multiple fundraising campaigns. Campaigns are shown on a new homepage and can be marked "active" or not.
Existing fundraisers can sign up for a new campaign without creating a new user.

Donor report

Added a Donor report to the admin section. Shows summary of donations by donor. Can be exported to CSV for creating tax receipts.

First public release

Release used in production at https://donations.triplecrownforheart.ca/team_fundraising/
Updated with information for open source release at https://github.com/dominikszopa/fundraising-website