docs(README): denote `make build` as optional

It's only necessary when making code changes.
Merge pull request #1198 from deis/readme_build_deis

docs(README): denote `make build` as optional
test(component): add dummy `make test` to deis/registry
test(controller): added unit tests to `make test-unit` for CI
test(utils) : add basic functional test files
refactor(tests): rewrite basic vagrant integration test in Go
fix(registry/test): use env vars for docker daemon connection info
test(refactor_code) : refactor code added dockercliutils
fix(logger/Makefile): update test-functional target for vendored $GOPATH
refactor(tests): added tests/utils go package
fix(Makefile): exit until loop if service becomes failed
fix(tests): try to scale "cmd" if "web" process type fails
chore(tests): update vendored docker to 1.0.1
refactor(tests): add etcd and mock utility packages