Clone the options object

Or else bad things will happen!
Expose the query on the options for a `destroying` event (fixes #231)
Merge pull request #233 from valet-io/patch/destroy-query

Expose the query on the options for a `destroying` event (fixes #231)
Added unit test
Added an actual check for inequality for `options`
Changed test description
Adding Model.collection static method

Creates a new collection where the Collection's model
is set as the current model.
add guard for empty options in Model.collection
Merge pull request #232 from johanneslumpe/clone-options

Clone the options object
some docs tweaks
Merge pull request #235 from tgriesser/model-collection

Adding Model.collection static method
docs prep for release
release 0.6.4