Support for multiple contains

[albertfdp]

In the following example scenario:

<Parent>
	<Foo>
 		<Item>One</Item>
	</Foo>
	<Foo>
		<Item>Two</Item>
	</Foo>
</Parent>

support doing:

expect(wrapper.find(Parent), 'to contain', [
	<Item>One</Item>,
 	<Item>Two</Item>
]);

https://github.com/airbnb/enzyme/blob/master/docs/api/ReactWrapper/contains.md