Overhaul all tests and remove cache

- Rename /test/data to /test/fixtures
- Remove unused fixtures and MockTransporter
- Mock all network requests (no external network required)
- Remove cache.js and replace with simple in-memory cache
- Add a couple media upload tests
- Add path parameter tests
- General cleanup of unused variables in all tests
assert.strictEqual the whole body. This test passes for many cases that should fail.