examples: add simple integration tests

[ebuchman]

We should check that we can run a successful basecoind init && basecoind start sequence for both basecoin and democoin since we keep having issues with this, eg. #1616 and #1503

We should also add a simple Gopkg.toml to basecoin and add a test that it works using a local vendored dir (in addition to being compiled using the top level one)

[cwgoes]

Also, ideally, dep init should produce a workable Gopkg.toml (maybe this is unlikely; if not edit Gopkg.toml by hand).