Go doesn't use relative import paths
For this to work correctly, the source code needs to be located under the right folder. In this case src/bitbucket.org/appveyor/test-go with GOPATH pointing at the folder src/ is in.
Go get (see build.cmd) will install additional code into the folder in the GOPATH. In this case, to github.com/koyachi/go-term-ansicolor.