The origin of this proposal is the name of the `swipe-left`, etc.
directional, boolean properties. They're missing another verb in their
name. In principle the right choice would be "recognize". That is what
the type name suggests, that's the term the documentation uses, so the
code should read `recognize-swipe-left: true;`. However that is a long
word. "Handle" is a verb that's simpler. It's also more generic (that's
a downside), but it's otherwise short enough to make things look
"right":
```
SwipeGestureHandler {
handle-swipe-left: true;
swiped => { something.naviate-left(); }
}
```
Therefore this patch proposes to rename the type to SwipeGestureHandler
and prefixes the boolean directional properties with "handle".
