BHV-725: Update the mouse coords in events when the body has been scaled. (Netcast 4)

Adds a new set of properties for calculating the clientX and clientY coordinates that are included on enyo events, which accurately reflect the position of the mouse on the screen.
The scale factors for X and Y are updated on load and on window resize.

**Why would we do this?**
Because of the scaling mechanism used for smaller screen devices (see below), the mouse coordinates don't track as expected.

```
.enyo-body-fit {
    height: 150%;
    width: 150%;
    -webkit-transform: scale3d(0.666666, 0.666666, 1);
    -webkit-transform-origin: 0 0 0;
}
```

This change gives us a set of scaling factors, which are automatically applied to enyo events' mouse coordinates, to compensate for the body having been scaled separately from the mouse.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>