Allow createItem() to take a silent:boolean parameter and pass that along to the addItem() within the method

[connortorrell]

Based on the fact that the addItem() method allows a silent parameter to be passed in to avoid a change event (which is a really nice feature I use a lot),

I would really like the consistency and flexibility for createItem() to have a silent option as well which would be passed along to the internal addItem() call in that method.

Right now I do this on my project with a monkey patch, but would be nice to see this supported in the package.