Custom gestures support

[FedorZaytsev]

Hi,

This PR add support for actions on swipe gestures. This is a logical extension for an existing 2-3 finger swipe for volume/brightness. To add an action on a gesture you need to create an object in preset with the following params:

{
     "type": "swipe",
    "fingers": 2,            // number of fingers required (2,3 or 4)
    "direction": "right",    // direction of swipe (right/left)
    "minOffset" 10,          // optional: minimal required offset for gesture to emit event
    "sourceApple": {         // optional: apple script to run
        "inline": "beep"
    },
    "sourceBash": {          // optional: bash script to run
        "inline": "touch /Users/lobster/test"
    }
}

In my opinion it is highly usable for some cases, for example for binding music track change on 2 finger swipes.

Legacy 2/3 finger swipe for volume/brightness is still working

[Toxblh]

I checked and looks like doesn't work width attribute for buttons/

[FedorZaytsev]

Can you explain in more details?

In my opinion, gesture elements are not supposed to be visible and should work with whole touch bar. This is how I did it and it doesn't make much sense to support width param.

Do you have another opinion about width param?

[Toxblh]

If I set "width" for elements with "align:left", so it's looks like doesn't effect