Added nice animations too.

Using respond to instead

Make add single and add multi work properly.
Multiple inputs for multiselect

Adds deselect still a WIP.

Moved the scss out of a mixin as it was really confusing the hell out of the CSS

Highlights first row when filtering

With this, builds will now fail if they break the SCSS style guide (at
least, the parts enabled by the linter).

Discussed in #14299.

This fixes the case when the user selects the same image consecutively. It failed because no 'change' event was fired.