Tests for latest code ported from UI codebase

- drag options: `x`, `y`, `handle`
- drag simulating mousemove: `document` -> `target.ownerDoucment`
- drag element removed during drag: `if ( $.contains( document, target ) ) {`
- mouse event options: `button` value `-1`.

Commits:
- 44594dd93
- dd3c930b8
- fce39f8af0
- 779bcef1d
- 386afd3b4
