Copies a set of named properties fom the source object to the destination object.

Example:

ImageComponent = Ext.extend(Ext.Component, {
initComponent: function() {
this.autoEl = { tag: 'img' };
MyComponent.superclass.initComponent.apply(this, arguments);
this.initialBox = Ext.copyTo({}, this.initialConfig, 'x,y,width,height');
}
});

Important note: To borrow class prototype methods, use {@link Ext.Base#borrow} instead.

@param {Object} dest The destination object.
@param {Object} source The source object.
@param {String/String[]} names Either an Array of property names, or a comma-delimited list
of property names to copy.
@param {Boolean} [usePrototypeKeys] Defaults to false. Pass true to copy keys off of the
prototype as well as the instance.
@return {Object} The modified object.
function(dest, source, names, usePrototypeKeys){
            if(typeof names == 'string'){
                names = names.split(/[,;\s]/);
            }

            var n,
                nLen = names? names.length : 0,
                name;

            for(n = 0; n < nLen; n++) {
                name = names[n];

                if(usePrototypeKeys || source.hasOwnProperty(name)){
                    dest[name] = source[name];
                }
            }

            return dest;
        }