Single tap registered as a pan gesture

[Lievesley]

Bug Report

If the head unit registers a small movement of the finger it is immediately recognised as a pan event instead of a single tap. This means that the iOS SDL SDK never sends our app single tap events.

Reproduction Steps

1. Perform single tap on head unit display
2. [SDLTouchManager sdl_handleTouchMoved] is called which sets
   _performingTouchType = SDLPerformingTouchTypePanningTouch;
3. Single tap delegate method is never called
   [strongSelf.touchEventDelegate touchManager:strongSelf didReceiveSingleTapForView:hitView atPoint:point];

Expected Behavior

There should be a threshold movement level below which pan gestures are not recognised to prevent them interfering with single tap touch events.

Observed Behavior

Pan gesture recogniser prevents single taps from being recognised.

OS & Version Information

• iOS Version: 11.0.3
• SDL iOS Version: v5.1
• Testing Against: Head unit

CLA

• I have signed the CLA

[Lievesley]

I'm creating a PR that fixes this.

[Lievesley]

PR is ready for review

[BrettyWhite]

@Lievesley i see you removed the CLA section, before we can merge any code after it is reviewed, that needs to be signed.

[Lievesley]

@BrettyWhite I just added it again.