Implement +from-unix for turning timestamps into
:: ::::
++ chrono ^?
|%
+ :: +from-unix: unix timestamp to @da
+ ::
+ ++ from-unix
+ |= timestamp=@ud
+ ^- @da
+ %+ add ~1970.1.1
+ (mul timestamp ~s1)
:: :: ++dawn:chrono:
++ dawn :: Jan 1 weekday
|= yer/@ud
