Give traceur.js a trim.

This removes a lot of properties from the traceur object. We used
to export everything onto it and then we stopped doing that. This
removes almost everything but the properties used from src/node.
chore(Makefile): make test-promise filter more strict + update docs

Make the promise test suite filter that skips invalid tests more strict to prevent
accidental test exclusion.

Also add a better explanation of why the sloppy (non-strict mode) tests are being skipped.
Merge pull request #930 from IgorMinar/aplus-promise-fix

chore(Makefile): make test-promise filter more strict + update docs
Merge pull request #923 from arv/cleanup-traceur-properties

Give traceur.js a trim.
Destructuring: The initializer must be an object.

The following should throw a TypeError:

```js
var {x} = 1;
```

since `1` is not an Object.

This is done by wrapping the initializer in a runtime call, called
`$traceurRuntime.assertObject`

Fixes #839