Add support for es-5 property with underliing observable.

[blazkovicz]

It is very convenient to use es5 properties with getter and setter set to observable. This way I can use property without braces and still subscribe for changes (directly to underlining observable). Knockout knows how to bind such properties - it has ko.expressionRewriting.twoWayBindings. Is there a possiblity for knockout-validation to support such properties?

[jmvtrinidad]

Instead you can use knockout-es5 without worrying parenthesis.