Geotime

Geotime provides a 128-bit signed integer timestamp compatible with Unix time_t and anchored at the Unix epoch. See the documentation here.

```rust use geotime::Geotime;

let dt = Geotime::from(0); asserteq!(dt.displaystring("%Y-%m-%d"), "1970-01-01");

let dt = Geotime::from((i64::MAX as i128) + 1); asserteq!(dt.displaystring("%Y"), "299.87 M years from now");

let dt = Geotime::from(-(i64::MAX as i128) * 100); asserteq!(dt.displaystring("%Y"), "29.99 B years ago"); ```