Fix for resetting filters on collection_view component

When applying new filters with a field which was not on the previous filter, this old filter gets merged into the new ones.

First filter:
`{ a: 'a' }`
Result of first filter:
`{ a: 'a' }`

Second filter:
`{ b: 'b' }`
Result of second filter:
`{ a: 'a', b: 'b' }`

This pull request partially fixes the problem, since the previous query gets stored on `@query` and merged with the new ones. The clients using it will still need to reset `@query` before filtering..