Add support for babel transpilation

[ctdio]

The test runner currently uses lasso for bundling test files and other dependencies. Allowing babel options to be passed into the test runner is a much needed feature. This can be done with https://github.com/lasso-js/lasso-babel-transform.

[ctdio]

This can be done once #7 is taken care of

[ctdio]

Closing since the lassoConfig allows for transforms to be added in.