Node-red-contrib-ui-svg click and dblclick in same element

[BartButenaers]

@BartButenaers

That was initially my reason to add a checkbox in the settings tabsheet, to require explicit activation of this behaviour. I haven't added it yet, but I should implement it. And deselect it by default, to make sure standard DOM behaviour is offered by default

By default the single click events/messages won't be suppressed anymore. The new behaviour should be enabled explicit:

The documentation on the readme pages has been updated.