Fix replacement of renamed/aliased imports (e.g. import { assert as somethingElse } from '@ember/debug')

[NullVoxPopuli]

Initial Report: emberjs/ember-cli-babel#372

[rwjblue]

This looks good thanks for working on it!

Could you also add usage (of both assert and deprecate) over to this test fixutre as well:

https://github.com/ember-cli/babel-plugin-debug-macros/blob/master/fixtures/ember-cli-babel-config/sample.js

That fixture runs in the ember-cli-babel style configuration, so its a good one to ensure things still work.