Fix Sponsors

- [x] Check sponsor organizations for uploaded logo to show on Event page, not just image URL
- [x] Remove "Aww, bummer, no projects" message from organizations who've sponsored or posted a job
- [x] Link Event page logos to organization profiles, which include descriptions, URLs and jobs, rather than URL alone (e.g. https://www.codemontage.com/organizations/amplify)
- [x] Show Coder Day of Service 2014 sponsorship on sponsor organization profiles
![coder_day_sponsorships_on_organization_profiles-2](https://f.cloud.github.com/assets/226228/1895859/bccf1c08-7b67-11e3-8237-e484e60764b1.png)