Use errors instead of panicing, log instead of fmt
Vcs for go 1.2.1
Make repoRoot public

gofmt -r 'repoRoot -> RepoRoot' -w *.go
Make repoRootForImportPath public

gofmt -r 'repoRootForImportPath -> RepoRootForImportPath' -w *.go
Make vcsCmd public

gofmt -r 'vcsCmd -> VcsCmd' -w *.go
Make RepoRoot fields public

gofmt -r 'a.vcs -> a.Vcs' -w *.go
gofmt -r 'a.repo -> a.Repo' -w *.go
gofmt -r 'a.root -> a.Root' -w *.go
Pull in the go tools vcs code