bringing mysql adapter to 53/63 passing

This PR includes a merge of ecto/master, updates to elixir 1.0.0, and a lot of work on integration tests for mysql. It's currently sitting at 10 failures for the 63 tests.

```
Finished in 35.9 seconds (2.2s on load, 33.6s on tests)
63 tests, 10 failures
```

The 10 tests failing seemingly revolve around relationships and the preloader.

The postgres adapter currently has 26 more tests, which includes types, worker, transaction, lock, and storage tests.