Don't perform two-way binding for radio value properties. [#422]
Shift the priority chain starting from the value binder. See new order below. [#422]

4000: blocking binders (if, unless, each-*)
3000: majority two-way binders (checked, unchecked)
2000: value binder (value)
1000: function / event handler binders (on-*)
Merge pull request #425 from mikeric/fix/radio-defaults-issues

Fix issue with radio defaults