- Except for social badges, omit logos by default (#983)
- Omit the logo from a social badge using the query string: `?logo=`
(#983)
- Opt in to named logos using the query string: `?logo=appveyor`
- Provide custom logo data as before: `?logo=data:image/png;base64,...`
- Rewrite badge data functions, with unit tests
Unit tests are covering the new code very well, though the underlying
functionality (logos) is untested.
Close#983