Enhancement/user guide missing#325

I implemented a sample, made  a jsfiddle: http://jsfiddle.net/tkrugg/45chpzks/2/
We should probably make a new jsfiddle with our ibmjs account, to keep things consistent.

I haven't yet updated doc/ToggleButton.md. I'll wait for the jsfiddle URL to be definitive then update this PR.