Radio button "checked" binding, allow to store values as boolean

I've made a small change to the library, it's just a small commit changing the "checked" binding..
If one has two radio buttons on a page defining two alternative/opposite options, it makes sense to set their values as boolean true/false..

Unfortunately, the radio checked binding will store these as a string.. I propose checking if the value of the radio is "true" or "false" to store the values as boolean type...

[*] checked binding: if radio button value is a boolean then save the value as boolean, not string