Also make tip a fast-finish allowed failure. That way, if CI fails on
tip due to a temporary issue with tip, it will not break build status.
However, it's still possible to see tip build status by looking at CI
details page.
Do not run go vet with Go 1.4 or older since it's not included in the
standard library, and it's no longer available in external standard
library.
Add godoc badge to README.md.
Harald Nordgren
Vytautas Šaltenis
Dmitri Shuralyov