Make days outside of current month selectable when visible

[missmatsuko]

Currently, days outside of the current month are visible, but cannot be clicked. I think it would be better UX if any visible days are selectable. #124 fix would allow an option to hide the days outside the current month, but I think they should be selectable when visible.

[uditalias]

+1

[manjunath-teachmint]

+1