High-level bindings to PushEvent

[ramirez7]

It doesn't look like there's a high-level binding for SDL_PushEvent (despite there being a low-level one)

It looks like there's high-level support for pushing user-defined events, but not for pushing vanilla SDL events.

There's also no easy way to use the low-level one since afaict, there's no high->low conversion for Events.

I think this would be a generally useful addition. For instance, I could imagine library code for a virtual keyboard/gamepad that handled touchscreen events and pushed synthetic keyboard/joystick events which were then handled without knowledge of the touchscreen layer.