Fix compile error in GestureEvent, and link native impl

It looks like the abc compiler has a bug that makes it impossible to make constructors native for classes that extend other classes with a non-default ctor: the compiler complains about the correct `super` call missing, even though there isn't a function body that could contain the `super` call in the first place.
Merge pull request #1293 from tschneidereit/nat

Fix compile error in GestureEvent, and link native impl