Date estimate

[ninpnin]

Implements the following metrics for the date gold standard:

$$ \begin{aligned} &\mathbb E[J(Y, \hat Y)] \\ &\mathbb P( J(Y, \hat Y) = 1) \\ &\mathbb P( J(Y, \hat Y) > 0) \\ &\mathbb P (Y \in \hat Y) \end{aligned} $$