Fix `eventQueue` staying blocked after a duplicate id error
Pass options into relations that are being created for a new model.

This fixes options being ignored in some cases; see the test
"`merge` on a nested relation" for an example. Ref #276.
Add a `parse` option to `findOrCreate` which defaults to `false`,
getting in line with `Backbone.Model`.

Fixes the "`parse` should only get called on top-level objects" test. Ref #276.