Add pitchstart and pitchend events

[lucaswoj]

zoom has zoomstart and zoomend

rotate has rotatestart and rotateend (see #2448)

pitch is all alone

[redbmk]

I'm actually having a hard time finding anywhere in the code that triggers a pitch event at all. I'm looking through the latest code for it, and map.on('pitch', data => console.log(data)) never fires for me in version 0.28.0.

[redbmk]

Ah, looks like that part of an open issue in #3357. Would that make this a duplicate then, since that issue also mentions making sure that pitchstart and pitchend fire?

[NoMemoryError]

Is this still being worked on? Any update on this ? Firing moveend zoomend event on every touch really effects the performance.

[mollymerp]

@Vypah yep I'm working on this as part of #4253 !

[NoMemoryError]

@mollymerp great 👍 I really hope that this will address #3435 once we start distinguishing between touch events and other events like moveend, zoomend. During multi-touch, eg. two fingers touching the screen at the same time, moveend is fired on every single animation frame for the duration of the gesture.