Switch to using the new steal

This makes Syn use the new steal, which will allow us to use the new
Pluginify for builds, as well as use an alternative syntax if we want.
Fixes #58
Run tests against the built syn

This adds the ability to run the tests against the built production syn.
It does this by pluginify-ing the tests and then running them on it's
own built.html page. Fixes #41
Merge pull request #41 from matthewp/test-build

Use built js to run tests