Adding a Makefile and basic tests.

This approach uses bats to create a generic docker-compose test. It
checks that images are pullable, projects are buildable, up works, and
if ports are exposed that something is listening.

The tests can be tailored for each example. As long as they are the same
though, you can edit lib/test.bats.example and then `make update-tests`
and all the tests will be synced.

Signed-off-by: Chad Metcalf <chad@docker.com>

Makefile

@@ -0,0 +1,7 @@
+.phony: test
+
+test:
+	@bats -T -r .
+
+update-tests:
+	@find . -maxdepth 1 -type d -not -path '*/\.*' -not -path '.' -not -path './lib' -exec cp ./lib/test.bats.example {}/test.bats \;