v0.2.0 - compatible with ember-mocha 0.2.0

Provides compatibility with ember-mocha 0.2.0, which in turn provides
compatibility with mocha 2.0.1 and chai 1.10.0.

It’s now necessary to call `mocha.setup()` prior to defining the
ember-mocha-adapter. This is done via `ember-mocha/mocha-setup.js`.