mbox.custom doesn't close if mbox.close isn't called inside the callback

[kounelios13]

Consider the following code:

mbox.custom({
  message:"Hello world",
  buttons:[{label:"Hey",color:'red',callback:function(){
      console.log("You clicked the red button");
  }}]
})

One would expect that after the "You clicked the red button" is shown to the console the mbox will close However this is not happening and some people may not expect it because it is documented. So documentation about mbox.custom should be updated(both readme and gh-pages)