Closes #1763 utilize ember server during testem run to get HTTP mocks

- My take on #1423 (heavily based on the work of @dustinfarris )
- Test Environment determines if Express Server spins up (false by default)
- Sets Express Access-Control-Allow-Origin to test runner port for all requests
- Refactors ```tasks/test-server.js``` to feel a bit more like ```tasks/test.js```

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