Option to keep the emoji picker open after emit an emoji

[Bissel]

This is pretty easy to to, just add an option like removeOnSelection defaults to true to keep the original behavior. And make an if-statement in the emitEmoji function:

if(this.removeOnSelection)
    picker.remove();

One of my testers mentioned that most people use multiple emojis and in my opinion it makes sens to have this option if wished.
And thanks a lot for the work on this picker.

[woody180]

Thanks. I have recently added to the parameters object.