Remove Spyke dependency

[pilaf]

Instead of having Spyke as a dependency that we patch on top of, copy the relevant bits of Spyke into this gem and modify it as needed. This should give us a lot more flexibility going forward.

Things we may want to do once we break free of Spyke:

• Rename Model#id to Model#record_id
• Alias Model.query as Model.where

Note: this will require adding specs for all of Spyke's features, which we currently don't have as we trust that Spyke tests those itself.