Why has CalenderView from Xamarin.Forms.Labs not been fully merged into Nuget release?

So I have set up my CalenderView Object in xaml like so:

<controls:CalendarView/>

Which works and looking at the Xamarin.Forms.Labs source file here I can see all the bindable properties so I would have thought that

<controls:CalendarView ShowNavigationArrows="True"/>

Would work as well. But this bindable property does not exist in the library from Nuget. Considering the last release was only a few months ago (V1.2.1-pre 1 released on Thursday, October 23 2014). I would have thought this would have been in here. Otherwise without navigation arrows (Or any bindable properties) the CalenderView is pretty much useless

Is there any reason why this control not been fully merged?