_format(buttons){
        buttons = buttons.slice(0,3); // phone users can only see 3 buttons, so lets limit this
        return buttons.map((btn) => {
            return {'buttonId':btn.id ? String(btn.id) : Util.generateHash(6),'buttonText':{'displayText':btn.body},'type':1};
        });
    }
Creates button array from simple array
@param {ButtonSpec[]} buttons
@returns {FormattedButtonSpec[]}
@example 
Input: [{id:'customId',body:'button1'},{body:'button2'},{body:'button3'},{body:'button4'}]
Returns: [{ buttonId:'customId',buttonText:{'displayText':'button1'},type: 1 },{buttonId:'n3XKsL',buttonText:{'displayText':'button2'},type:1},{buttonId:'NDJk0a',buttonText:{'displayText':'button3'},type:1}]