Adds dependency on core-js.

[MicahZoltu]

If you don't directly depend on core-js (which the skeleton app does) then aurelia-loader will fail to load because it can't find core-js. I was able to work around this by manually telling SystemJS that aurelia-loader depends on core-js, but as a user I shouldn't have to do that.

[MicahZoltu]

https://github.com/aurelia/loader/blob/master/src/loader.js#L2 suggests that this module definitely depends on core-js.

[MicahZoltu]

Workaround:
package.json

{
  "jspm": {
    "overrides": {
      "npm:aurelia-loader@1.0.0-beta.1": {
        "dependencies": {
          "aurelia-metadata": "^1.0.0-beta.1",
          "aurelia-path": "^1.0.0-beta.1",
          "core-js": "^1.2.6"
        }
      }
    }
  }
}

[EisenbergEffect]

After looking over the code, I can't find anywhere where this module actually needs things provided by core-js in order to function. So, instead of officially adding the core-js dependency, I remove the core-js import statement.

[MicahZoltu]

👍 Thanks!