Implemented rudimentary charCode to be returned by keydown event.
Remove a memory leak where saved touch data would never be released
Remove dead code branches for touch events
Bring touch events back into the main switch block
Reset properties to null instead of deleting them
Emit drags only for real drags (mouse is down)
Emit deltaX/Y and diffX/Y values for mousemove events, too
Add deltaX/Y to touch events as well (pointermove/drag)
Add to changelog
Add experimental `elementsUnderPointer` renderer option
Add private/internal module to wrap svg intersection checks
Prevent unnecessary object creation
Extend property matchers so that they can also check property values
Start to break events out of the svg renderer

- for future reusability with other renderers
- to increase code organization and legibility
Remove functions that are no longer in use
Simplify property tests
Add mouse button properties
Add clone methods
Add `PointerEvent.fromDomMouseEvent()`
Add `PointerEvent.fromDomTouch` method