Ability to configure split button in config.toolbar property

[mlewand]

Type of report

Feature request

Provide description of the new feature

It would be nice to give the ability to create a split button from the configuration alone.

An example config would be:

config.toolbar = [
    [ 'Source', '-', 'Bold', 'Italic', {
		type: 'splitbutton',
		name: 'JustifySplitButton',
		label: 'Justify', // Human readable label.
		items: [ 'JustifyLeft', 'JustifyRight', 'JustifyBlock', 'JustifyCenter' ],
		default: 'JustifyRight'
	} ]
];

name, label and default property should be optional, in case the name is skipped the name should be simply generated, like SplitButton1 etc.